Which of the following is NOT a sign of potential terrorist activity?

Acquiring supplies for legitimate purposes does not indicate potential terrorist activity because this behavior typically aligns with regular and lawful business practices or personal needs. Legitimate procurement of supplies, such as materials for construction, office supplies, or other everyday items, is common and does not inherently raise suspicion. In contrast, the other options presented are behaviors associated with reconnaissance, testing security, or suspicious financial activities that could indicate planning or intention to engage in illicit acts. Surveillance of security areas, funding through small transactions which can disguise larger funding efforts, and testing security measures can all reflect a methodical approach to circumventing security and planning harmful actions, thus distinguishing them as red flags in security assessments.