A penetration tester must gain entry to a client's office building without raising attention.

Comprehensive and Detailed Explanation:

The appropriate first step for a low-profile physical access attempt is conducting surveillance to gather information such as entry points, peak/low occupancy times, security guard patterns, camera placement, and typical foot traffic. Surveillance (visual observation, external photography, publicly available schedules) informs a safe, low-risk entry plan and helps the tester choose tactics that minimize attention.

Why not the others first:

A. Interacting with security employees to clone a badge — directly engaging security staff to manipulate them is an escalation and could alert personnel; it’s also ethically/contractually risky if done without prior scoped approval and planning.

B. Trying to enter the back door after hours on a weekend — acting without reconnaissance increases likelihood of detection or legal exposure.

C. Collecting building blueprints to run a site survey — blueprints are useful but often hard to obtain and not the initial low-effort step; surveillance provides immediate, actionable behavioral intelligence.

CompTIA PT0-003 Mapping: Physical security assessments — perform reconnaissance and site survey activities first to develop low-visibility access strategies that adhere to the engagement rules of engagement and legal constraints.