India maintained its early cultural contacts and trade links with Southeast Asia across the Bay of Bengal. For this pre-eminence of early maritime history of Bay of Bengal, which of the following could be the most convincing explanation/explanations

(a)

As compared to other countries, India had better ship-building technology in ancient and medieval times.

(b)

The rulers of southern India always patronized traders, brahmin priests and Buddhist monks in this context.

(c)

Monsoon winds across the Bay of Bengal facilitated sea voyages.

(d)

Both (a) and (b) are convincing explanations in this context.