Sediments in a subsiding sedimentary basin a. experience decreased pressure and temperature because of the geothermal gradient. b. lose any oil they might contain because metamorphic conditions destroy organic molecules present. c. become high-grade foliated metamorphic rocks at depth. d. undergo no changes when they're at shallow depth.

B. lose any oil they might contain because metamorphic conditions destroy the organic molecules present.

Explanation:

Sediments in a subsiding sedimentary basin do the following:

1. lose any oil they might contain because metamorphic conditions destroy the organic molecules present.

2. undergo burial metamorphism when they reach depths greater than 8 to 15 km

3. experience increased pressure and temperature

4. undergo diagenetic changes when they're at shallow depth.