Testing Quizzes Quantitative Testing

Question:
A grandfather has 5 sons and daughters and 8 grandchildren.. They have to be arranged in arrow such that the first 4 seats and last four seats are to be taken by grandchildren and the grandfather would not sit adjacent to any of the grandchildren.

Option A):
4*6!*8!
Option B):
5*4!*8!
Option C):
8*4!*5!
Option D):
4*8!*5!

Correct Answer is Option D):
4*8!*5!