WILL GIVE BRAINLIEST TO RIGHT ANSWER
Consider U = {x|x is a positive integer greater than 1}.

Which is an empty set?

{x|x ∈ U and is prime}
{x|x ∈ U and 2x is prime}
{x|x ∈ U and can be written as a fraction}
{x|x ∈ U and 2x can be written as a fraction}