To determine the rate at which a sum of N100.00 would need to be deposited for 5 years to raise an interest of N7.50, follow these steps:

1. Use the simple interest formula:

$$I=P\times r\times t$$

where:
- $I$ is the interest (N7.50),
- $P$ is the principal amount (N100.00),
- $r$ is the rate (expressed as a decimal),
- $t$ is the time in years (5 years).

2. Substitute the known values into the formula:

$$7.50=100\times r\times 5$$

3. Solve for $r$:

$$7.50=500r$$

$$r=\frac{7.50}{500}=0.015$$

Convert $r$ to a percentage:

$$r=0.015\times 100\mathrm{\%}=1.5\mathrm{\%}$$

So, the correct answer is:

C. 1.5%