Answer:
B. The rate of increase is 4%
D. 2100 represents the initial deposit.
Step-by-step explanation:
Look at the equation modeling the savings account.
A = 2100(1.04)
1.04 represent the percent the current account is of the previous one.
That is a 4% increase, which remains the same, so B is one of the correct answers.
2100 was the original deposit, so D is correct as well.
Knowing this, B and D are correct.