This writer established the heroic couplet as a standard form of English poetry and also introduced the alexandrine and triplet into the form.

Correct option is D

Explanation:
The correct answer is John Dryden.

John Dryden (1631–1700) was a major literary figure of the Restoration Age, known for standardizing the heroic couplet as the dominant verse form in English poetry. He introduced refinements such as:

The alexandrine (a line of 12 syllables, often used for variation).
The triplet (a set of three rhyming lines within a heroic couplet structure).
His influence made the heroic couplet the primary mode of poetic expression until the 18th century, especially in satire and neoclassical poetry.

Information Booster:

John Dryden was an English poet, literary critic, translator, and playwright who in 1668 was appointed England's first Poet Laureate.
He is seen as dominating the literary life of Restoration England to such a point that the period came to be known in literary circles as the Age of Dryden. Romantic writer Sir Walter Scott called him "Glorious John".[3]

What is a Heroic Couplet?
          - A pair of rhymed lines in iambic pentameter (10 syllables per line).
            Example from Dryden’s Absalom and Achitophel:
           "A man so various, that he seemed to be / Not one, but all mankind’s epitome."

Dryden’s Contributions to Heroic Couplets:

-Used smooth, regular, and epigrammatic couplets.
-Introduced the alexandrine to add variation.
-Popularized triplets for emphasis and rhetorical effect.

Famous Works of Dryden:
-Absalom and Achitophel (1681) – Political satire.
-Mac Flecknoe (1682) – Satirical attack on poet Thomas Shadwell.
-The Hind and the Panther (1687) – Religious allegory.

Influence on Later Poets:

-Alexander Pope further perfected the heroic couplet in The Rape of the Lock and The Dunciad.
-Dryden’s style and techniques influenced neoclassical poetry.
  Example:
"A brave man struggling in the storms of fate, / And greatly falling with a falling state, / While hopes and fears a busy scene create."

Additional Knowledge:

Voltaire  – Voltaire was a French Enlightenment writer, philosopher, satirist, and historian. Famous for his wit and his criticism of Christianity (especially of the Roman Catholic Church) and of slavery, Voltaire was an advocate of freedom of speech, freedom of religion, and separation of church and state.
Voltaire was a versatile and prolific writer, producing works in almost every literary form, including plays, poems, novels, essays, histories, and even scientific expositions.

John Flaxman  – John Flaxman RA was a British sculptor and draughtsman, and a leading figure in British and European Neoclassicism. Early in his career, he worked as a modeller for Josiah Wedgwood's pottery. He spent several years in Rome, where he produced his first book illustrations. He was a prolific maker of funerary monuments.

Joseph Addison  – Joseph Addison was an English essayist, poet, playwright, and politician. He was the eldest son of Lancelot Addison. His name is usually remembered alongside that of his long-standing friend Richard Steele, with whom he founded The Spectator magazine. His simple prose style marked the end of the mannerisms and conventional classical images of the 17th century.