Explanation: \(\text{Hints: } a = \frac{\Delta v}{t} \\ \text{Solve: আমরা জানি, } a = \frac{\Delta v}{t} \\ \text{এখানে, বেগের পরিবর্তন, } \Delta v = (12\hat{i}-4\hat{j}) - (4\hat{i}+2\hat{j}) \\ \implies \Delta v = 8\hat{i} - 6\hat{j} \\ \therefore |\Delta v| = \sqrt{(8)^2 + (-6)^2} = 10 \\ \therefore a = \frac{10}{8} = 1.25 \, \text{m/s}^2 \\ \text{Ans. (C)}\)