are from S-pole to $\mathrm{N}$ -pole of the magnet.
do not exist
depend upon area of cross-section of bar magnet.
are from $\mathrm{N}$ -pole to $\mathrm{S}$ -pole of the magnet.
Solution
Inside a bar magnet, the magnetic field lines(A) are not present(B) are parallel to the cross-sectional area of the magnet(C) are in the direction from $\mathrm{N}$-pole to S-pole(D) are in the direction from S-pole to $N$-pole