3) circuit load corresponds to one of the switch numbers that's on
We're told that 1 and 3 are both off, and we're looking to figure out which answer choice could be two switches that are both on.
Starting with (A), we have 2 and 7. Let's try it.
If 2 and 7 are both on, this means that 4 must be off (the contrapositive of rule 2).
We have 2 and 7 on, and 1, 3, and 4 off with 5 and 6 not yet assigned.
Looking at our rules, we see that with 2 and 7, we already satisfy the last rule (the switch whose number corresponds to the circuit load of the panel is itself on). We can just put 5 and 6 in the out/off group, so we have 2 and 7 in and all of the other switches out. This is why (A) works and is the correct answer choice.
Does this make sense? Let us know if you have any other questions!