What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_1, y_1 will not drink water. For all y_1, y_1 is a poet if and only if y_1 will drink water. If David were a mechanic, then Robert is a poet. If Robert were a poet, then David is a mechanic.
For all y_1, if y_1 were a poet, then y_1 is drinking water. For all y_1, if y_1 drinks water, then y_1 is a poet. For all y_1, y_1 is not a poet.