Answer:
Third option:

Step-by-step explanation:
Notice if we invest 2,000 then the first month then after the first 0.4% interest is earned we will have in the account:
2,000(1+0.004) = 2,000(1.004)
I just applied the simple interest formula.
Then after the second month we will have:

And so on each month.
So at the end of the first year (12 months) we have:

But we also earn an additional 1.5% in the year, so we will have:

At the end of the second year we will have:
![2,000[(1.004)^{12}(1.015)]^2](https://tex.z-dn.net/?f=2%2C000%5B%281.004%29%5E%7B12%7D%281.015%29%5D%5E2)
At the end of the third year:
![2,000[(1.004)^{12}(1.015)]^2](https://tex.z-dn.net/?f=2%2C000%5B%281.004%29%5E%7B12%7D%281.015%29%5D%5E2)
And so on,
So if the number of years is denoted with x, at the end of x years we will have the following amount in the savings:
![2,000[(1.004)^{12}(1.015)]^x](https://tex.z-dn.net/?f=2%2C000%5B%281.004%29%5E%7B12%7D%281.015%29%5D%5Ex)
We use our calculator to simplify that inside the brackets:

Rounding to the third decimal place we get: 1.065
So notice the amount in the savings after x years will be:

Since they want it in function notation we just write the A(x) that denotes the amount in the savings:
