The correct answer is 'inbreeding depression'. This is when more recessive traits are manifesting in the phenotype. Recessive traits can only occur in offspring if both parents contain the recessive gene, and this is much more likely under reduced genetic diversity due to inbreeding. Many alleles confer a selective advantage in the heterozygous and/or homozygous-dominant state, whereas the homozygous-recessive state confers less or even no advantage.
