What is the answer ?

Answer: Almost any number less than 58.
37, 40, 45, 50, 53, 56 or 57, for example.
(The question says: "which of the following. . .? but that set of choices is not visible in he screen shot.)
Step-by-step explanation:
The median is the middle number when the numbers are lined up in order.
So 58 has to have 3 numbers higher and 3 numbers lower.
reorganized in order the given numbers are 54,55,58,64,68,70
There are already three higher numbers, so you need a lower number to put to the left of 58. it would look like
50,54,55,58,64,68,70.