Option B is correct because the requirement is specifically to prevent visit creation when a Visit overlaps with a Time Off Territory record. Salesforce Life Sciences documentation references Time Off Territory overlapping rules as the standard mechanism that prevents creating visits during TOT events. Salesforce's Winter '26 Customer Engagement package patch notes also mention an issue where a visit could be created during a Time Off Territory event, bypassing the overlapping rule that should have prevented creation. That confirms TOT overlapping rules are the expected standard control for this scenario.
Because the business wants a hard stop, the overlapping rule behavior must be set to "Error." This means the rep receives an error and cannot proceed with scheduling the visit while it conflicts with the TOT time block.
Option A is incorrect because a custom validation rule on Visit would duplicate a standard Life Sciences calendar/TOT capability and may not handle the full mobile scheduling experience correctly. Option C is also not the best answer because "Block Activity on Conflict" on the TOT record type is not the documented standard configuration in the Life Sciences Visit/Calendar settings. The correct standard configuration is to use TOT Overlapping Rules and set the overlap behavior to Error. This prevents scheduling visits during the rep's logged time off.
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