What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y, if y plays squash, then y is a poet. For all y, y is not a scientist. For all y, y is a scientist if and only if y will write a letter. For all y, y is a poet if and only if y will write a letter. For all y, if y climbs a mountain, then y is playing squash.
For all y, if y climbs a mountain, then y is a poet. For all y, if y were a scientist, then y is writing a letter. For all y, if y were a poet, then y is writing a letter. For all y, if y writes a letter, then y is a scientist. For all y, if y writes a letter, then y is a poet. For all y, y will not write a letter.