To express the set of all natural numbers \( N \) that are less than 5, we need to consider the definition of natural numbers. Typically, natural numbers start from 1. Therefore, the natural numbers less than 5 are 1, 2, 3, and 4.
This can be expressed in set notation as:
\[ { x \mid x \in N, x < 5 } \]
Among the options provided, the correct one that represents this set is:
C. \({ x \mid x \text{ is an element of } N, x \leq 5 }\)
However, to specifically indicate numbers strictly less than 5, option D could be more aligned:
D. \({ x \mid x \text{ is an element of } N, x < 5 }\)
So the best answer would be D, which correctly states that \( x \) is a natural number less than 5.