Question

rebirth of a soul in a new body
a. reincarnation
b. issues
c. caste
d. nirvana

Explanation:

The question defines the rebirth of a soul into a new physical body. Option a describes this exact religious/philosophical concept, option b refers to problems or topics for discussion, option c is a social stratification system, and option d is the state of liberation from the cycle of rebirth in some Eastern religions.

Answer:

a. Reincarnation