Answer :
The answer is D cause you are given that the polynomial y=ax^+bx+c has the value y=1 a+x= -1. It means that (substitute this value of x= -1 into the polynomial) 1=y=a×(-1)+c =a*1-b+c=a-b+c.
again:a-b+c=1
again:a-b+c=1