Comprehensive and Detailed Explanation From Exact Extract:

Spyware is malicious software specifically designed to covertly collect information from a user’s device or network without authorization. It can monitor browsing habits, capture credentials, log keystrokes, or harvest system and application data, then send this information to an attacker.

Why C is correct: Spyware’s core purpose is unauthorized information collection, aligning exactly with the description in the question.

Why the others are incorrect:

A. Ransomware – Encrypts or locks data/systems and demands payment for restoration; its primary goal is extortion, not information collection.

B. Brute force attack – A method of systematically guessing passwords or keys; it is an attack technique, not software focused on secretly gathering data.

D. Man-in-the-middle – An attacker intercepts and possibly alters communication between two parties; while it can be used to capture information, it is a network attack position, not specifically malware installed on a system for ongoing data collection like spyware.