Two identical balls “A” and “B” having velocities of $0.5 m{s}^{-1}$ and $-0.3 m{s}^{-1}$ respectively collide elastically in one dimension. The velocities of B and  A after the collision respectively will be

• A

  $-0.5 \mathrm{m}{ \mathrm{s}}^{-1}\text{and }0.3 \mathrm{m}{ \mathrm{s}}^{-1}$

• B

  $0.5 \mathrm{m}{ \mathrm{s}}^{-1}\text{and- }0.3 \mathrm{m}{ \mathrm{s}}^{-1}$

• C

  $-0.3 \mathrm{m}{ \mathrm{s}}^{-1}\text{and }0.5 \mathrm{m}{ \mathrm{s}}^{-1}$

• D

  $0.3 \mathrm{m}{ \mathrm{s}}^{-1}\text{and }0.5 \mathrm{m}{ \mathrm{s}}^{-1}$