Answer:
4
Step-by-step explanation:
Codons describe the triplet sequence of bases present in an mRNA that code for proteins. They do this by specifying specific amino acids.
To answer this question, we need to know the genetic code. This can be found in various formats (usually tables) online or in textbooks. An example is attached.
Threonine is an amino acid with the three letter code Thr, and the one letter code T.
As you can see in the table, 4 codons (ACU, ACC, ACA, ACG) code for threonine