Concept: The question tests on the basics of Probability
Solution:
Probability of getting a 6 on the first throw or the second throw or both is equivalent to saying getting at least 1 six in 2 throws = 1 - P(not getting a six in either throw)
P(getting a six) = 1/6, therefore P(not getting a six) = 5/6
Required probability = 1 - (5/6 * 5/6) = 1 - 25/36 = 11/36
Option D