What is the difference between cout and cerr?
a)cout is unbuffered output and cerr is buffered output
b)cout is standard output and cerr is not a standardoutput
c)cout is not a standard output and cerr is standard output
d)cout is buffered output and cerr is unbuffered output

D) Cout is buffered output and cerr is unbuffered output

Explanation:  

Cout is buffered output as it is used  for the production of the output on the device which displays the standard output. Unbuffered error stream (cerr) is a stream of the standard output which is basically used for the displaying/ production of the output.

The answer would be A

Step-by-step explanation:

If you add the positive numbers in answer a you get the sum of 18. Then add the negative numbers in answer A getting the answer 18. 18-18 equals zero