Here, 

⇒ 2.8×1.5+ 8% of 250= ?

It can aslo be written as,

$\begin{array}{l}\Rightarrow \text{2.8}\times \text{1.5 + }\frac{\text{8}}{100}\times 250\\ \\ \Rightarrow 2.8\times 1.5+8\times 2.5[\because \frac{250}{100}=2.5]\\ \\ \Rightarrow 4.2+20=24.2\end{array}$

Hence, Option A is correct.