Boys can inherit the recessive allele (c) that causes red-green colour blindness from their mother, not from their father. The allele for normal red and green vision is C. Which of the following genotypes are possible in men?
c only c only
BC or c only
CCC or cc only
DCC, Cc or cc only
c only c only
BC or c only
CCC or cc only
DCC, Cc or cc only