Computer information

The sum of weights in self complementing BCD code must be

(A) 7

(B) 8

(C) 9

(D) 10

. Binary coded decimal is a combination of __________
a) Two binary digits
b) Three binary digits
c) Four binary digits
d) Five binary digits

Which symbol is used to make absolute cell reference?
a) $ b) *
c) % d) &