Assertion (A) Kashmir came under several dynasties including the rule of Central Asia and Bactrian empire.
Reason (R) Kashmir was under the rule of Kushans and the Huns as they were powerful and defeated native rulers of Kashmir.

Assertion (A): Kashmir came under several dynasties including the rule of Central Asia and Bactrian empire.
Reason (R): Kashmir was under the rule of Kushans and the Huns as they were powerful and defeated native rulers of Kashmir.

Both Assertion (A) and Reason (R) are true. Kashmir's history indeed includes periods of rule by various dynasties from Central Asia and the Bactrian empire. Additionally, the assertion that Kashmir was ruled by powerful dynasties like the Kushans and the Huns, who defeated native rulers, is also true. The reason provides an explanation for why Kashmir came under the rule of these dynasties, thereby supporting the assertion.

Hence, Option A: Both (A) and (R) true and (R) is the correct explanation of (A) is the correct choice.