What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: There is at least one x_2 for which if x_2 were sad, then x_2 is a writer. For all x_2, if x_2 were curious, then x_2 is sad. For all x_2, x_2 is an electrician or x_2 is curious. For all x_2, if x_2 were an electrician, then x_2 is a writer.
There is at least one x_2 for which if x_2 were curious, then x_2 is a writer can be inferred via the existential transitivity rule.