Question

Barbara has curly hair. Her genotype for this trait is CC. What do you infer from this?

Answer 1

Since she has curly hair, it's a dominant trait. 
CC is upper case hinting at both are dominant traits. Hence, she has dominant traits, and not recessive. 

Answer 2

Barbara has dominant alleles for curly hair because CC is all capitals. and  The two alleles of the gene are homozygous dominant