What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Jennifer is fast. Charles is an astronaut if and only if Mary is working. Mary is not working. For all x_18, x_18 is an office clerk if and only if x_18 is an astronaut.
Jennifer is fast and Mary is not working. Mary is not working and Jennifer is fast. If Charles were an astronaut, then Mary is working. If Mary works, then Charles is an astronaut. Charles is not an astronaut. For all x_18, if x_18 were an office clerk, then x_18 is an astronaut. For all x_18, if x_18 were an astronaut, then x_18 is an office clerk.