Early $5G$ users should be aware that their coverage may be limited compared with $4G$ coverage, at least initially. Why will $5G$ networks likely be less widespread at first?

a$.$ more cell towers will need to be installed

b$.5G$ equipment is inexpensive but complicated to install

c$.$ devices must be compatible with both $4G$ and $5G$

d$.$ major providers are not launching $5G$ coverage yet