I think it's a mistaken reversal. The stimulus is saying that because the necessary condition occured, the sufficient condition must have occured as well. It's a reversal of the conditional statement in the first sentence.
It makes sense that answer choice A is correct:
Have a dog -> know the true value of companionship
The argument errs by saying that because Alicia knows the true value of companionship, she must have a dog. That's wrong..it's possible that she knows the true value of compansionship for some other reason..