Final answer:
The question seems to ask for the rebroadcast frequency for look-outs on OUC, which requires specific organizational protocol to answer accurately. If the student is referring to probability calculation involving timeframes, this would be a mathematics question focusing on probability theory.
Step-by-step explanation:
The question is inquiring about the frequency at which the Official Use Only Channel (OUC) should rebroadcast look-outs for serious incidents or critical missing persons. An official rebroadcasting schedule can vary depending on policy and the specifics of the situation. However, the question does not provide enough context to determine a correct response as it does not correlate with the options provided related to time increments such as 'hourly' or 'every 2 hours.' More information is required to answer the student's question accurately, and it is recommended to consult the protocol of the specific agency or organization in question for their policies on rebroadcasting look-outs.
However, the student may be asking about the probability of an occurrence within a specific time frame, as suggested by the other examples provided, which relate to a mathematics problem about probability calculation. If that's the case, and we're looking at the probability of an event occurring within a certain timeframe (for example, between 4 to 7 p.m.), this falls under the study of mathematics and particularly probability theory.