You could use either Single Strand Conformation Polymorphism as it will detect differences in a single stranded nucleotide sequence. The difference will show on an electrophoresis gel even though they number of nucleotides is the same. It is the difference in the nucleotides that will allow for the DNA to form into a different conformation, meaning a different appearance on the gel. Secondly, you could use Allele Specific Oglionucleotide Hybridisation which is when synthetic probes are made to hybridise to a known mutation. If you know the mutations, you can design three probes for the three single base pair mutations and see which one hybridises to the nucleotide strand.
List ALL genotypes possible with these two alleles.
a. +/+
b. +/C217T
c. C217T/C217T