Which of the following best explains why ortho-substituted anilines are generally weaker bases than aniline in aqueous solution?

1. AThe ortho group always increases the electron density on nitrogen
2. BThe ortho group sterically hinders protonation and solvation of the $-\mathrm{NH}{}_2$ group, destabilising the anilinium ion
3. CThe ortho group makes the lone pair more available through the $+M$ effect of nitrogen
4. DThe ortho group converts the amine to an amide