Cystic fibrosis is inherited in an autosomal recessive pattern. males who have cystic fibrosis are usually sterile. furthermore, the disease is often lethal before the age of reproduction. even though people with the disease rarely reproduce, cases continue to arise because (see book section: module 9.9)
a. new mutations continually introduce this harmful condition into the populationb. the harmful allele "hides" inside heterozygous individuals and one-fourth of the offspring of two heterozygotes should be afflictedc. mosquitoes can transfer the disease from person to person
d. people continue to make inappropriate lifestyle choices

I would say B

Explanation:

I know for sure it's not C

a metamorphic rock would be formed.

osteogenesis imperfecta (oi) refers to a congenital ailment of bones. in the condition, the bones become brittle or fragile. this ailment is a general result of the defect or mutations in the genes (colia1 or colia2). this mutation results in imperfect collagen formation either in quantity or quality wise.  

there are eight kinds of oi defects, and each kind varies with certain distinctions in symptoms. the usual symptoms include frequent bone fractures, loss of hearing in infants, protruding eyes, discoloration of the white in the eyes, respiratory issues, loosening of the joints, short stature, and other symptoms.