(a) Since CFLs are closed under regular difference, so L1−L2=CFL−regular=CFLs
So option (a) is false.
(b) Since context free language is closed under regular intersection so L1∩L2=CFL∩REG=CFL
So option (b) is true.
(c) Context free language is not closed under complementation.So ∼L1 is not context free language.So option (c) is flase.
(d) Regular language are closed under complementation.So ∼L2 is regular.
So option (d) is true.