1-Methylcyclohexene is treated with BH3· THF and then H2O2/NaOH to give A; A is oxidised with PCC to B; B reacts with excess CH3MgBr followed by…

Hydroboration-oxidation of $1$-methylcyclohexene is syn and anti-Markovnikov, giving $trans$-$2$-methylcyclohexanol $\mathbf{A}$ (racemic). PCC converts it to $2$-methylcyclohexanone $\mathbf{B}$, so the stereochemical history of $\mathbf{A}$ is irrelevant. $\mathrm{CH_3MgBr}$ adds to $\mathrm{C=O}$ to give $1,2$-dimethylcyclohexan-$1$-ol $\mathbf{C}$, which has two stereocentres ($\mathrm{C1}$ and $\mathrm{C2}$) and no symmetry element, hence $2^2=4$ stereoisomers. Acid-catalysed dehydration proceeds through the tertiary carbocation at $\mathrm{C1}$; loss of the $\mathrm{C2}$ hydrogen gives the tetrasubstituted, most stable alkene $1,2$-dimethylcyclohexene $\mathbf{D}$ (achiral), not the exocyclic alkene. Hence the answer is $4$ and $1,2$-dimethylcyclohexene.