The average of first 121 odd natural numbers, is:

Given:

We need to find the average of the first 121 odd natural numbers.

Formula used:

The average of the first n odd natural numbers is equal to the middle number in the sequence.

Calculation:

The sequence of the first 121 odd natural numbers is: 1, 3, 5, ..., 241.

The middle number in the sequence is determined by the formula:

⇒ Middle number = (n^th odd number) = 2 × n - 1

⇒ Middle number = 2 × 121 - 1

⇒ Middle number = 241

⇒ Average = Middle number = 241

∴ The correct answer is option (3).