c
\(\overrightarrow{ a } =\frac{\overrightarrow{ F }}{ m }=\frac{2 \hat{ i }+3 \hat{ j }+5 \hat{ k }}{2}\)

\(=\hat{ i }+1.5 \hat{ j }+2.5 \hat{ k }\)

\(\vec{r} =\overrightarrow{ u } t +\frac{1}{2} \overrightarrow{ a } t ^{2}\)

\(=0+\frac{1}{2}(\hat{ i }+1.5 \hat{ j }+2.5 \hat{ k })(16)\)

\(=8 \hat{ i }+12 \hat{ j }+20 \hat{ k }\)

\(b=12\)