A sudden contraction in a pipe line from a $100$ mm to a $70$ mm diameter has a $k-$factor of $....?$

$($A$)0\mathrm{.}55$

$0\mathrm{.}28$

$($C$)0\mathrm{.}22$

$($D$)0\mathrm{.}15$

$0\mathrm{.}36$