谁能战胜这个？：）

yyaannmm

求助大侠！我有一道数学题，弄不明白。
Which of the following integers does NOT have a divisor greater than 1 that is the square of an integer?
a. 75
b. 42
c. 32
d. 25
e. 12
我看了多变，都不明白是什么意思？请高手给我指点一下。