You likely know that “enemy” is similar in meaning to “rival,” so the key to answering this question is to understand how the prefix "arch-" changes the meaning of the word “enemy.” In this instance, the meaning is unchanged. "Arch-" means chief or primary, so your “archenemy” is your biggest enemy or rival. To provide further help, “bellow” means to yell; “debris” is the fallen parts of things after they are broken; a “nomad” is someone who wanders from place to place without making a home; “catastrophe” means disaster.

The Greek root "dynam" means energy, so the word “dynamic” means having energy, exciting, or “active.” “Vacant” means unoccupied; “inert” means lifeless and having no energy; "dominant” means in control and in charge; and "despondent" means very sad and pessimistic.

The Greek prefix micro- means very small, as in "microscope" which is a tool used to look at things that are very small. So, "microscopic" means tiny, very, very small. To provide additional help, "susceptible" means vulnerable, at risk; "immune" is an antonym of "susceptible" it means not vulnerable, cannot be affected by (usually a disease); "massive" means very large; "gorgeous" means beautiful, attractive.

The Greek prefix ego- means self. So, someone who is "egotistical" is self-centered, selfish. Additionally, "selfless" means not selfish, generous; "helpless" means not able to be helped.

The Greek prefix di- means two. So, a "dilemma" is a problem with two possible solutions, a predicament, a quandary. To provide additional help, a "notion" is an idea or a feeling; a "suggestion" is an idea expressed to help someone with a problem. 

The Greek prefix arch- can have two meanings. It either means chief as in "monarch" or ancient, old-fashioned as in "archaic." "Archaic" means old-fashioned and out of date, obsolete, no longer needed or used. To provide additional help, "impressive" means inspiring admiration, making people impressed; "domineering" means bossy, dominating, in-charge; "confounding" means confusing, bewildering; "recessive" means (of a gene) not dominant, hidden. 

The Greek prefix mis- means wrong, bad, as in "mistake" which means error. A "misnomer" is an inaccurate name, an error in naming something. So, the best possible answer is "error." You might also notice the root word -nom- which often means name. So, simply a "misnomer" is a wrong name, an error in naming. 

The Greek prefix melan- means black, dark, so "melancholy" means a dark mood, sadness, depression, misery. Additionally, the other four answer choices all mean deep happiness. 

The Greek prefix opt- means eyes, sight, or related to sight. So, "optical" means of or relating to sight. The synonym here is not perfect, but sometimes you have to find the answer that is "closest" to the word in question. 

The Greek prefix pater- means father, so "paternity" means fatherhood. The Greek prefix mater- means mother, so "maternity" means motherhood. Another example of a pater- word is "patriarch" which refers to a man in charge of a group.