Final answer:
The correct match for the analogy 'plague is to contagious' is 'confidant is to trustworthy', reflecting the noun-adjective relationship where 'plague' is the noun and 'contagious' is the descriptive adjective, akin to how 'trustworthy' describes the essential characteristic of a 'confidant'.
Step-by-step explanation:
When considering the analogy 'plague is to contagious' related to options provided, we are looking for a pair that matches the relationship of a noun to its adjective descriptor. 'Plague' is a noun, and 'contagious' is an adjective that describes a key characteristic of the plague, especially in the context of pneumonic plague, which is directly contagious from person to person.
Comparing this to the provided options, 'confidant: trustworthy' most accurately reflects this relationship. A 'confidant' is a noun, and 'trustworthy' is an adjective describing an essential characteristic of a confidant. Therefore, 'plague is to contagious' as 'confidant is to trustworthy' is the correct analogy, which means the answer is option 1) confidant: trustworthy.