Identify the incorrect word /phrase indicated by A, B, C or D in the following sentence: Jahanara $\underset{A}{\overset{had}{\to }}$ better $\underset{B}{\overset{to change}{\to }}$ her subject $\underset{C}{\overset{If}{\to }}$ she plans $\underset{D}{\overset{to be admitted}{\to }}$ to a good university