Answer:
The reason why dominant alleles that cause lethal disorders are less common than recessive alleles that cause lethal disorders is that most individuals carrying a lethal dominant allele have the disorder and die before they reproduce, whereas individuals carrying a lethal recessive allele are more likely to be healthy and reproduce (first option).
Explanation:
The severity with which a lethal disorder occurs will determine whether or not the individual suffering from it can have offspring.
With respect to genetic disorders that are lethal, when presented as dominant alleles most of the offspring can inherit them and, consequently, prevent reproduction when the disorder is manifest in the individual.
Diseases that are transmitted to the offspring as recessive alleles are more common, because they can be present in the individual without the disease, in the form of a healthy carrier. This ensures that these types of recessive disorders are more common than those linked to dominant alleles.