Which of the following can have an exponential distribution?

A) Time between phone calls coming in to a technical support desk.
B) Time until the first customer arrives at the bank in the morning.
C) Lifetime of a new battery.
D) All of these choices are true.

The exponential distribution is often used to model the time between events in a Poisson process, which is a process where events occur continuously and independently at a constant average rate. All the given options (A: Time between phone calls, B: Time until the first customer arrives, C: Lifetime of a new battery) can be modeled as Poisson processes, where the time between events (phone calls, customer arrivals, or battery failures) follows an exponential distribution.