​5, 25, 7, 49, 9, 81, 11, ?​

Correct option is C

Given series:

$$5, 25, 7, 49, 9, 81, 11, \ ?$$​

Observing the positions:

1. Odd-positioned terms:

$$5, 7, 9, 11, \dots$$​

2. Even-positioned terms:

25, 49, 81, ?

These are squares of the preceding odd-positioned terms:

​$$5^2 = 25$$​

​$$7^2 = 49$$​

​$$9^2 = 81$$​

​$$11^2 = 121$$​ (expected next term)

Step 2: Finding the Missing Term

Since the missing term is in the 8th position (even position), it should be the square of the preceding odd number (11):

​$$11^2 = 121$$​

Final Answer:

​$$\boxed{121}$$​