An insect crawls a distance of 4m along north in 10 s and then a distance of 3m along East in 5s. The average velocity of the insect is:

• A

  $\frac{7}{15}{\mathrm{ms}}^{-1}$

• B

  $\frac{1}{5}{\mathrm{ms}}^{-1}$

• C

  $\frac{1}{3}{\mathrm{ms}}^{-1}$

• D

  $\frac{4}{5}{\mathrm{ms}}^{-1}$