A Scientist Makes Three Artificial MRNA Strands

Multiple Choice

A scientist makes three artificial mRNA strands:
(x) 5' AAAUUUAAAUUUAAAUUUAAAUUUAAA 3'
(y) 5' UUUCCCUUUCCCUUUCCCUUUCCCUUU 3'
(z) 5' AUAUAUAUAUAUAUAUAUAUAUAUAU 3'
When he analyzes the polypeptides produced,he finds that:
X produces a polypeptide that is 50% phenylalanine and 50%lysine.
Y produces a polypeptide that is 50% phenylalanine and 50% proline.
Z produces a polypeptide that is 50% isoleucine and 50% tyrosine.
Based on these results only,the best conclusion to make is that

A) AUA codes for isoleucine
B) AAA codes for phenylalanine
C) AAA codes for lysine
D) AAA codes for lysine and AUA codes for isoleucine
E) AAA codes for phenylalanine and AUA codes for isoleucine