Truth table for system of four `NAND` gates as shown in figure is :
.
A. `{:("A","B","Y"),("0","0","1"),("0","1","1"),("1","0","0"),("1","1","0"):}`
B. `{:("A","B","Y"),("0","0","1"),("0","1","0"),("1","0","0"),("1","1","1"):}`
C. `{:("A","B","Y"),("0","0","0"),("0","1","1"),("1","0","1"),("1","1","0"):}`
D. `{:("A","B","Y"),("0","0","0"),("0","1","0"),("1","0","1"),("1","1","1"):}`