If Glucose Labeled with ¹⁴C at C-1 Were the Starting

If glucose labeled with ¹⁴C at C-1 were the starting material for amino acid biosynthesis,the product(s) that would be readily formed is (are) :

A) serine labeled at the carboxyl carbon.
B) serine labeled at alpha carbon.
C) serine labeled at the R-group carbon.
D) All of the above
E) None of the above