The ans is E

Could you please explain your reasoning

statement 1:

r+s is even

we know that for the result to be even either both the numbers should be even or both the numbers should be odd
so r&s are both even or r&s are both odd
And moreover we have no info about t

Insufficient

statement 2:

s+t is even

As per the same logic either s &t are both even or s& t are both odd
There is no info about t

Insufficient

Combining both the statements we get

r,s and t are all even or r,s,t are all odd
when r,s & t are all even r+s+t results in an even number
when r,s & t are all odd r+s+t results in an odd number

So the ans is E..

E. OA pls

OA - E.

Thanks for the explanation raju232007. I messed up when I combined both the equations and your explanation helped me understand my error.