Need help explaining as well Which of the following is an example of a missense mutation?

A substitution of a serine amino acid for a glycine amino acid
A codon mutated from CCG to CCA, both coding for glycine
A substitution of glycine amino acid for a stop codon
An insertion or deletion of nucleotides that is not a multiple of three

A common and well-known example of a missense mutation is sickle-cell anemia, a blood disease. People with sickle-cell anemia have a missense mutation at a single point in the DNA. This missense mutation calls for a different amino acid, and affects the overall shape of the protein produced.

Explanation:

I would have to say A.  Fell free to correct me if i'm wrong :)

a. the production of carbon dioxide through the process of photosynthesis