b
\(\begin{array}{l}
\,\,\,\,\,\,\,\,\,\,\,\,\,Here,\\
Initial\,velocity,\,\overline u  = 2\hat i + 3\hat j\\
Acceleration,\,\overline a  = 0.3\hat i + 0.2\hat j\\
Time\,,\,t = 10\,s\\
Let\,\overline v \,be\,velocity\,of\,a\,particle\,\\
after\,10\,s.
\end{array}\)

\(\begin{array}{l}
{\rm{Using,}}\,\overline v \, = \overline u  + \,\overline a t\\
\therefore \,\,\,\overline v  = \left( {2\hat i + 3\hat j} \right) + \left( {0.3\hat i + 0.2\hat j} \right)\left( {10} \right)\\
\,\,\,\,\,\,\,\,\, = \,2\hat i + 3\hat j + 3\hat i + 2\hat j = 5\hat i + 5\hat j\\
Speed\,of\,the\,particle\,after\,10\,s = \left| {\overline v } \right|\\
\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \sqrt {{{\left( 5 \right)}^2} + {{\left( 5 \right)}^2}}  = 5\sqrt 2 \,units
\end{array}\)