Step 1: Test the Assertion on its own.
India did sit at the centre of sixteenth century Indian Ocean trade, with ports handling goods moving between Asia, Africa, and Europe, so the Assertion holds.
Step 2: Test the Reason on its own.
India's location, bridging the eastern and western halves of the ocean trade network, is also a true fact.
Step 3: Check the link between them.
That very location is what allowed India to become a trading hub in the first place, so the Reason is not just true, it directly explains the Assertion.
Step 4: Conclude.
Both statements are true and connected. The correct answer is option (A).