[tex]p=501\cdot503\cdot\cdots\cdot597[/tex]
[tex]q=\underbrace{501\cdot503\cdot\cdots\cdot597}_p\cdot599\cdot601[/tex]
So we have [tex]q=359,999p[/tex]. Then
[tex]\dfrac1p+\dfrac1q=\dfrac{359,999}{359,999p}+\dfrac1q=\dfrac{359,999+1}q=\dfrac{360,000}q[/tex]
and the answer is D.