If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?

A) at most, 2 alleles for that gene
B) up to 18 chromosomes with that gene
C) up to 18 genes for that trait
D) a haploid number of 9 chromosomes
E) up to, but not more than, 18 different traits