Why doesn't the third binary addition problem from the left produce overflow

When I add them I get 00000 with a discarded carry out of 1 so I don't understand how 2 negative numbers can add up to 0 unless the answer is in 2's complement form. But I don't understand how it would be since the sign bit of the answer is 0.

Part B Now compute additions and detect overflows for these five bit, two's compliment numbers 10 11 +101+10101 10 10 1 +101110000 10 100 overflow? overflow? overflow? overflow