Consider PBR with diameter $D=0\mathrm{.}5cm,$ length $L=2m$ and porsity $40\%,$ if the density of catalyst $=2$gca$\frac{t}{c}{m}^3.$ What is the weight of the catalyst $?$

a$)W=200g$

b$)W=70g$

c$)W=47g$

d$)$ None of the above