Based on your text, can be defined as full engagement with one's own internal mental processes in a nonconfrontational way, which often involves a reduction in

The answer in the spaces provided are the following—mindfulness; experienal avoidance. It is because mindfulness is the one that is termed when one is engaged with its own internal mental process in which they are usually linked with experiental avoidance that is being reduced.

the answer your looking for is c. : )