Final answer:
The base of the exponential term (-3)^7 is -3 (option a).
Step-by-step explanation:
The base of the exponential term (-3)7 is -3 (option a).
When we have an exponential term in the form of an, the base is the number a. In this case, the base is -3. The exponent n is the power to which the base is raised. In this case, the exponent is 7. Therefore, the base of the exponential term (-3)7 is -3.