Correct option is A
Explanation of the Correct Answer: · "Doctor" should be "The doctor" because it refers to a specific person.
· "A exhibition" is incorrect; it should be "an exhibition" since "exhibition" starts with a vowel sound.
· "The medicines" is correct as it refers to specific medicines.
Thus, the corrected sentence is:
"The doctor she spoke to at the exhibition was very knowledgeable. The medicines prescribed by him have proved excellent for my father."
Why Are the Other Options Incorrect? · (b) "Doctor she spoke to at the exhibition..." → Incorrect; missing "The" before "Doctor."
· (c) "At exhibition" → Incorrect; missing "the" before "exhibition."
· (d) "A medicines" → Incorrect; "medicines" is plural, so "A" is incorrect.
Thus, the correct answer is: (a) The doctor she spoke to at the exhibition was very knowledgeable. The medicines prescribed by him have proved excellent for my father.