An unknown compound X is one of the four compounds listed in the Table below. A mixture of X with benzoic acid melts at 89 degrees Celsius, a mixture of X with phenyl succinate melts at 90 degrees Celsisus, and a mixture of X with m-aminophenol melts at 120 degrees Celsisus. Give the identity of X and explain your reasoning.
Table
Compound m.p. degrees Celsisus
o-toluic acid 102
benzoic acid 121
phenyl succinate 121
m-aminophenol 122