Ring assemblies

How shall we call the structure (a)?

(a)

biphenyl (trivial) 1,1′-biphenyl (ring assembly, PIN) phenylbenzene (substitutive)

We can name it substitutively, i.e. substituting one hydrogen atom in the parent hydride benzene with phenyl group: phenylbenzene. This name, however, does not reflect the obvious symmetry of the molecule.

Similar story with (b) whose substitutive name, cyclopentylidenecyclopentane, is barely pronounceable.