Consider the following premises. Mary is a police officer if and only if Jessica is drinking water. If Jessica reads a book, then Mary is a police officer. For all x_19, x_19 will read a book if and only if x_19 will drink water. Can we infer the following from them? If we can, name the inference rule being used: If is not true that Jessica is drinking water if and only if Mary is a police officer.
That contradicts the premises. Therefore the answer is no.