Which Set Is Infinite? A) $\{ x \mid x$ Is an Improper Fraction

Short Answer

Which set is infinite? A) $\{ x \mid x$ is an improper fraction $\}$
В) $\{ 3,5,7 , \ldots , 99 \}$
C) $\varnothing$
D) $\{ x \mid x \in N$ and $x < 20 \}$