If $7$ is at the hundreds place in a number, what is its place value?

The correct option is B $7\times 100$
As we know, place value of a digit:

• At units place = Digit $\times$ 1
• At tens place = Digit $\times$ 10
• At hundreds place = Digit $\times$ 100
• At thousands place = Digit $\times$ 1000

Therefore, the place value of $7$ at the hundreds place in a number = $7\times 100.$