Folded limestones that are exposed high elevations in the himalayas were originally deposited as sediments in a a. deep ocean trench along the southern margin of india. b. marine basin between india and eurasia. c. cenozoic fault basin between africa and arabia. d. late paleozoic syncline north of the tibetan plateau.

Option (B)

Explanation:

The Himalaya is the youngest mountain belt, formed due to the sharing of a convergent plate boundary between the Eurasian Plate and the Indo-Australian plate, where the Indo-Australian plate sinks below the Eurasian plate due to its greater density. This mountain belt started to form some 50 million years back.

The rocks at the upper part of the Himalaya are comprised of sedimentary rocks which comprise a good amount of fossil assemblages such as limestones. These limestones must have been deposited prior to the formation of this mountain belt, in a shallow or deep marine type of environment, which were later compressed and forced the rocks to eventually rise up and formed the present-day scenario.

Thus, these fossils must have been deposited as sediments in a marine basin between India and Eurasia.

Hence, the correct answer is option (B).