The correct answer is: Both (A) and (R) are true, but (R) is not the correct explanation of (A).
Assertion (A) is true. Kashmir came under the rule of several dynasties, including the Kushans, the Huns, and the Mughals.
Reason (R) is also true. The Kushans and the Huns were powerful empires that conquered many lands, including Kashmir. However, (R) is not the correct explanation of (A). Kashmir came under the rule of these empires for a variety of reasons, including their military power, but also because of political alliances and trade.
In conclusion, both (A) and (R) are true, but (R) is not the correct explanation of (A).