Solution:
Given:
[tex]4+3.3=21[/tex]To make the equation true, we need to place parentheses at the right place in the equation.
Hence, the equation is;
[tex]\begin{gathered} (4+3).3=21 \\ Solvi\text{ng the parentheses first,} \\ 7.3=21 \\ 7\times3=21 \\ 21=21 \\ \\ \text{Hence, this is TRUE.} \end{gathered}[/tex]Therefore, the correct answer to make the equation true is;
[tex](4+3).3=21[/tex]Hence, OPTION A is correct.