Assertion: Haryana was carved out of Punjab in 1966 on linguistic basis.
Reason (R): The demand was for a Punjabi-speaking state.

Correct option is A

The correct answer is The correct answer is (a) Both A and R are true, and R is the correct explanation of A 
Explanation:
. Assertion (a) is true; Haryana was formed as a separate state from the Hindi-speaking areas of the composite Punjab state on November 1, 1966.
. The reorganisation was recommended by the Shah Commission (Punjab Boundary Commission) in 1966, following the principles of linguistic demarcation.
. Reason (R) is true; the primary demand from the Sikh leadership (specifically the Shiromani Akali Dal) was for a separate, Punjabi-speaking state (Punjabi Suba).
. As a result of this demand and the subsequent commission, the existing state was divided into two: the new Punjabi-speaking state of Punjab and the new Hindi-speaking state of Haryana.
. R is the correct explanation for A because the demand for a Punjabi-speaking state necessitated the separation of the non-Punjabi-speaking (Hindi-speaking) areas, thus leading to the creation of Haryana based on the same linguistic principle. 
Information Booster:
. The States Reorganisation Act, 1956 primarily recommended reorganisation of Indian states along linguistic lines. The case of Punjab was deferred at that time but eventually implemented a decade later.
. November 1st is celebrated as Haryana Day and Punjab Day.
. Chandigarh was made a Union Territory to serve as the capital for both the newly formed states.