1. NFPA 13, Standard for the Installation of Sprinkler Systems (2022 Edition).
Section 14.2.12.2.3: "The vertical centerline of the HVLS fan shall be centered approximately between four adjacent sprinklers." This section explicitly states the requirement that directly supports the correct answer.
2. Fire Protection Research Foundation. (2011). Sprinkler Protection for Storage with HVLS Fans (Phase 1).
Page 2, Section 1.1: The report, which provides the technical basis for the NFPA 13 rules, discusses the test setups. It states, "The fans were located with the hub centered in a four-sprinkler array..." This research confirms the principle of centering the fan between four sprinklers to study and mitigate its impact.