I need help with math question? xD (6th grade math question)

In round one of a phone tree, a person calls 4 people. In round 2, each person in round 1 calls 4 more people, and so on. How many calls will be made in round 4?

a. 1,024 calls
b. 512 calls
c. 625 calls
d. 20 calls


ITS CONFUSING!!!!!!!!!!! AND PLEASE EXPLAIN!

4^5
1024; A.

e.g.
http://calculus.info/algebra/logs/log3/l…

wait haha. this is embarrassing, I'm a senior in high school and I'm not sure if I'm doing this right lmao. So wouldn't 1x4x4x4x4 = 256? Why is it 4^5? As an earlier poster explained >.<