Which category of time signal governs the below stated specifications?

Which category of time signal governs the below stated specifications?
A. Look-Up Table
B. Use of Recursive formula
C. Equation comprising n^th sample values in terms of function of n.
D. Sequence of numbers that occurs at regular interval (T seconds)

a. Periodic Signals
b. Discrete Time Signals
c. Exponential Signal
d. Continuous Time Signals

Correct Answer : b. Discrete Time Signals

Explanation :

Discrete time signals follow all these specifications while continuous time signals include look-up table & depict their representation through waveforms. Also, periodic signals gets repeated after fixed interval of time whereas, exponential itself shows the complex numbers in the form of exponential terms.