Which statement are correct about the following compounds ?
A. `(I)` is not isolable because trans `-` cyclohexane is too strained.
B. `(II)` is isolable because trans `-` unit can be bridged by six `C` atoms. Eight`-` memebered and larger rings can have a trans`-`substituted `(C=C)` in the ring.
C. `(III)` is not isolable, exocyclic double bonds `(` double bond at the bridgeheat `)` are unstable because of high strain `(` due to ring and double bond joining the two rings `)`.
D. `(IV)` is isolable, although there is a double bond at a bridgehead `(` joining two rings`)` but one of the bridgeheadds has no `C` atom and bridgeheat `C` atoms can flatten without ring strain.
