Which statement about $4$ G wireless communications is correct?

a$.$ Major $4$G networks use circuit$-$switching rather than packet$-$switching approaches.

b$.$ The bandwidth and latency of $4$G networks enable rapid streaming of VR content.

c$.$ A two$-$hour movie can be streamed in less than $3$ seconds over a $4G$ network.

d$.$ Eventually, $4$G will make worldwide roaming as well as universal access possible.