one cat and one rat is present in surrounding one day cat want to eat the rat in that time rat entered into the one bone .the rat will go like this

1 2 3 4 5 [this r some positions]
9 8 7 6
10 11 12 13
17 16 15 14
18 19 20 21...........
............................................ like that finally the cat catch the rat at 500 position.then find the 500 position is under comes which place ?

a)5
b)3
c)1
d)2
e)2 & 4
f)a,b,c & d
g)a & c
h)all