LSAT Practice Test 2026 - Free LSAT Practice Questions and Study Guide

In Formal Logic, the term "Unless" signifies necessity. This is because the use of "Unless" indicates a necessary condition for the stated result to occur. In other words, the occurrence of the result is dependent on the fulfillment of the condition introduced by "Unless." This makes option A, which suggests necessity, the correct answer.

The other options are not correct because "Unless" in Formal Logic does not indicate possibility (option B), sufficiency (option C), or probability (option D). Instead, it specifically denotes a necessary condition that must be met for a certain outcome to happen.