A uranium$-235$ atom is moving forwards in a reactor with a velocity of

$6\mathrm{.}2$ x $105$ ms$-1$ when it undergoes spontaneous fission into a krypton $($Kr$)$ atom and a Barium $($Ba$)$ atom. The Kr atom is ejected backwards at a velocity of $3\mathrm{.}3$ x $106$ ms$-1$ whilst the Ba atom is projected forwards $($atomic masses are:

U $=235$ u$,$ Kr $=95$ u and Ba $=140$ u$)$

The velocity of the barium atom after fission has occurred is about:

A$\mathrm{.}1\mathrm{.}9$x$105$ ms$-1$ B$\mathrm{.}8\mathrm{.}7$x$106$ ms$-1$ C$\mathrm{.}3\mathrm{.}3$x$106$ ms$-1$ D$\mathrm{.}2\mathrm{.}6$x$106$ ms$-1$