Pls.explain this question:

77. Refer to the diagram which shows the synthesis of part of a protein molecule. 


Which of the following is the first part of the protein molecule that would be translated from mRNA_​2?

$$\begin{gathered} \left(a\right) A{A}_4-A{A}_2-A{A}_7-A{A}_6 \\ \left(b\right) A{A}_6-A{A}_7-AA2-A{A}_4 \\ \left(c\right) A{A}_3-A{A}_1-A{A}_6-A{A}_8 \\ \left(d\right) A{A}_8-A{A}_5-A{A}_1-A{A}_3 \end{gathered}$$