Which of the following statements is correct?

(a) The product is

A strongly activating group, competing with a weakly activating group, controls the orientation. The position 6 will be sterically hindered.

(b) The C-H bond in benzene involves ${\mathrm{sp}}^2 -\mathrm{s}$ character while in cyclohexane it is ${\mathrm{sp}}^3-\mathrm{s}$. The bond C-H in benzene is expected to be shorter and thus stronger than in cyclohexane.

( c) There are only two isomers.

( d) 1,2,4-tribromobenzene gives three isomers.

The compound 1, 2, 3-tribromobenzene gives two isomers.