the first step to solving this is to factor out the perfect square of 5²

next,, factor out the perfect square of p³

the root of a product is equal to the product of the roots of each factor
√5² √p² √p
now reduce the first index of the radical and the exponent with 2
5√p² √p
then reduce the second index of the radical and exponent with
5p√p
this means that the correct answer to your question is 5p√p
let me know if you have any further questions
:)