Final answer:
The correct answer is option A) Tremor Mod.
Step-by-step explanation:
The question is referring to mods for the game Terraria. When comparing the options given, it's important to consider both the size (or 'minor' status) and the number of objects they add to the game.
The Thorium Mod is known for being extensive, featuring over 2000 new items, and is thus not considered a 'minor' mod. Terraria Overhaul revamps many elements of the base game but does not add as many objects as a mod focused on content addition. Shadows of Abaddon adds a significant amount of content with a focus on lategame items and challenges.
On the other hand, Tremor Mod was once considered a significant mod but has been discontinued and is less relevant in the current modding scene. None of these options are typically classified as 'minor' mods; however, in terms of the quantity of objects added, Tremor, being discontinued with less active development, might comparatively be considered minor against others that are actively expanding.