The $\mathrm{x}$ and $\mathrm{y}$ coordinates of a particles at any time $\mathrm{t}$ are given by $\mathrm{x}=7\mathrm{t}+4{\mathrm{t}}^2$ and $\mathrm{y}=5\mathrm{t}$. where $\mathrm{x}$ and $\mathrm{y}$ are in metre and $\mathrm{t}$ in second. The acceleration of particle at $\mathrm{t}=5 \mathrm{s}$ is

• A

  zero
• Correct answer
  B

  $\mathrm{8 }\mathrm{m }{\mathrm{s}}^{-2}$
• C

  $\mathrm{20 }\mathrm{m }{\mathrm{s}}^{-2}$
• D

  $\mathrm{40 }\mathrm{m }{\mathrm{s}}^{-2}$

Hence, the correct answer is option: 'B'.