"Some alleles of a gene are dominant, and others are recessive" is the only true statement here. The other two, "If the recessive allele appears on one of the genes, the offspring will display the trait" and "Both dominant alleles need to be present for the offspring to inherit the dominant trait" can each be ruled out easily with the former being that both recessive alleles have to appear for the offspring to display the trait and the latter being that a dominant and a recessive can work with the dominant still showing.
