Try simplifying the language the way you would during the test. No As are Bs would translate simply into "If A, then not B." Contrapositive is "If B, then not A." 7sage lawgic uses a / for negation.
... write the argument out in lawgic. Then, check the answer choice ... don't align with your lawgic (usually this quickly leaves you ... few remaining answer choices into lawgic. These question types are time ...