That's what I do all day. Every day. Dozens of times a day. I try to reply to every email from every entrepreneur who sends us an investment opportunity. I don't achieve that goal and sometimes I don't even get close.
But at least half the time, probably 2/3 of the time, I just reply with a no. And I try to explain in each and every one why the answer is no. Because email is time consuming, the explanation is often one or two lines. Something like "it doesn't fit into our investment strategy" or "we don't invest in content businesses" or "it's too early state" or "it's too late stage". I realize that these reasons are barely useful. But at least it's better than "no thanks"..."