Given a char variable ch, which of the following converts ch to upper case if ch is a lower-case letter?

a)	if (ch >= 'a' || ch <= 'z') ch = ch - 'A' + 'a';

b)	if (ch >= 'a' && ch <= 'z') ch = ch - 'a' + 'A';

c)	if (ch >= 'a' || ch <= 'z') ch = ch - 'a' + 'A';

d)	if (ch >= 'a' && ch <= 'z') ch = ch - 'A' + 'a';