Select the number that can replace the question mark (?) in the following series.

25, 5, 49, 10, 81, 20, 121, ?

The given series is a alternate series with the two series are 25, 49, 81, 121, ...  and  5, 10, 20, ...

The next term of the given series is the next term of 5, 10, 20, ...

In the series 5, 10, 20, ....

5 x 2 = 10

10 x 2 = 20

Number in the series is twice the previous number.

Similarly, the next number = 20 x 2 = 40

$$\therefore\ $$Next number of the given series is 40

Hence, the correct answer is Option B