Answer:
Option B, gametes are produced with a missing or incorrect sequence in a part of a gene that produces a single amino acid.
Step-by-step explanation:
Somatic mutations don't cause any genetic disorders due to the mutations happening to cells that aren't the sperm or the egg. Therefore, you can eliminate A and C.
Most mutations stem from the problem of DNA replication, where a codon is erroneously copied during the process of duplicating DNA. However, that does not lead to the deactivation of other genes.
Option B is correct.