a) 24.3 is a rational number
[tex]\frac{243}{10}[/tex]b)
[tex]\begin{gathered} \sqrt{2}=1.41421 \\ \sqrt{2}\text{ is irrational} \end{gathered}[/tex]c) 7 is a rational number
d)
[tex]\begin{gathered} \sqrt{25}=5 \\ \sqrt[]{25}\text{ is rational} \end{gathered}[/tex]Answer: Letter B