What is the product of an acyl substitution reaction a new carboxylic acid derivative, a mixture of two carboxylic acid derivatives, or no reaction if the new group in the tetrahedral intermediate is the following?
a. a stronger base than the substituent that is attached to the acyl group
b. a weaker base than the substituent that is attached to the acyl group
c. similar in basicity to the substituent that is attached to the acyl group