What is the contrapositive of the following: "ilf r is rational then the decimal expansion of r is repeating." a. if the decimal expansion of r does not repeat then r is irrational. b. if r is irrational then the decimal expansion of r does not repeat c. if the decimal expansion of r is repeating then r is irrational. d. if the decimal expansion of r is repeating then r is rational. e. if r is rational then the decimal expansion of r is repeating. o f. if r is rational then the decimal expansion of r does not repeat. what is the contrapositive of the following: "lf i form a study group then i raise my grades." a. if i work alone then i lower my grades. b. if i raise my grades then i form a study group. c. if i lower my grades then i work alone. od. if i form a study group then i lower my grades. e. if i form a study group then i raise my grades. f. if i raise my grades then i work alone.