We need to identify the correct set for which all the numbers are solutions to x < -3.
Notice that, as a number gets farther from zero to the left side of the number line, it gets more negative, i.e., smaller.
Thus, the solutions to the given equation must be numbers with an absolute value greater than 3, but with a negative sign:
In options A and D, there are non-negative numbers (0 in A; 3/4 and 2 in D ). Thus, they are not the correct option.
For option B, notice that -3 belongs to that set. Thus, this is not the correct option.
In option C, all the numbers are less than -3:
Answer: C