Question #$28(1$ Point$)$

Consider the following state transition diagram for a credit$-$card only, unattended gasoline pump:

Assume that you want to develop the minimum number of tests to cover each transition in the state transition diagram. Assume further that each test must start at the beginning state, waiting for customer, and each test ends when a transition arrives at the beginning state. How many tests do you need?

a$)4$

b$)7$

c$)1$

d$)$ Infinite