Description for Correct answer:
Sum of first n natural numbers = \( \large \frac{n + 1}{2} \)

So, average of first n natural numbers = \( \large n + 1\)= \( \large\frac{n + 1}{2} \)

Average = \( \large \left( \frac{50 + 1}{2} \right) = \frac{51}{2} = 25.5 \)