Consider the following premises. For all y, y will climb a mountain if and only if y is an electrician. For all y, if y were an office clerk, then y is a carpenter. There is at least one y for which if y were a carpenter, then y is an electrician. Can we infer the following from them? If we can, name the inference rule being used: For all y, the fact that y were an office clerk does not imply that y is climbing a mountain.
That contradicts the premises. Therefore the answer is no.