Group Of Children

A group of 630 children is arranged in rows for a group photograph session. Each row contains three fewer children than the row in front of it. What number of rows is not possible?

A. 3
B. 4
C. 5
D. 6
E. 7

note - this is not an Official Guide Question - it's from Complore.com which is where many of the other questions are from that are being posted. I just wanted to let people out there know where a lot of the questions are from that they're answering. And before someone says "THIS IS COPY AND PASTED" I would like to tell everyone - YES IT IS... as are all of the other questions similar on here. Is there anything wrong with it? Well you be the judge. If this is the way people want to take the competition... well that's unfortunate. This will be my one and only post that's copy and pasted simply for the purpose of gaining posts for the contest. Any further Math/Verbal questions that I post are truly for my understanding!

Solution Copy and Pasted as well...

[spoiler]
Let n be the number of rows in the arrangement of the 630 children. If n is odd, the number of children in the middle row multiplied by n is 630. Thus, an odd value of
n is possible, only if n is a factor of 630.

So, n = 3, 5, 7 are possible.
For n = 4, the possible arrangement is 162, 159, 156 and 153.
Hence n = 6 is the only option left out and is not possible.
Note: For n – 6, we get numbers which are not integers.[/spoiler]