In an Experimental Inertial-Confinement Fusion Reactor,inertial Confinement Has a Useful $\tau$

Multiple Choice

In an experimental inertial-confinement fusion reactor,inertial confinement has a useful duration of $\tau$ = 2.0 $\times$ 10^-10 s.What must the density of the fusible material be in order to meet Lawson's criterion?

A) 2.0 $\times$ 10²⁴ particles/cm³
B) 5.0 $\times$ 10²³ particles/cm³
C) 6.0 $\times$ 10²³ particles/cm³
D) 2.5 $\times$ 10²³ particles/cm³
E) 7.0 $\times$ 10²³ particles/cm³