Q.

Assertion (A): The tangents drawn at the end points of a diameter of a circle are parallel.

Reason (R): Diameter of a circle is the longest chord.

1 Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).  
2 Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).  
3 Assertion (A) is true, but Reason (R) is false.  
4 Assertion (A) is false, but Reason (R) is true.  

Ans.

(2)

As PQ and AB are tangents and OD and OC are radius of the circle,

OD ⟂ PQ and OC ⟂ AB

⇒ ∠ODP = ∠OCA = 90°

∴ ∠ODP + ∠OCA = 180°

⇒ ∠ODP and ∠OCA are co-interior angles.

⇒ PQ and AB are parallel.

Assertion is true.

Also, diameter of a circle is the longest chord.

Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).