Both statements in the question are individually true, but Statement II is not the correct explanation of Statement I.
Statement I is true because the Kushanas were indeed the first rulers to issue coins that bore their names and images. This is an important development in the history of coinage as it signifies the shift from anonymous coins to coins that were connected to specific rulers.
Statement II is also true since the Kushanas were known for issuing gold coins. However, this statement does not explain why the first coins to bear the names and images of rulers were issued by the Kushanas. It is a separate fact about the coins issued by the Kushanas but does not provide an explanation for the assertion made in Statement I.
Therefore, the correct answer is option 2, where both statements are individually true but Statement II is not the correct explanation of Statement I.