In this sentence, "alternative" best fits the blank because fresh fruit is being compared to cookies, but "fresh fruit is a healthy comparison to candy or cookies for dessert", is not grammatically correct, therefore "comparison" is not the correct answer.
To say that "fresh fruit is a healthy alternative to candy or cookies for desert", creates a true statement that properly compares fruit to candy/cookies, in a way that is grammatically correct.
1.) A.) Algernon eavesdrops on Jack while he's conversing with Gwendolyn. 2.) D.) I believe is the correct answer. Algernon made up the invalid Bunbury in order to travel into the country whenever he pleased.