Answer :
A period in problem solving when the problem solver is not actively working on the problem is called (B) incubation.
This term refers to taking a step back from the problem, potentially allowing the subconscious mind to work on finding a solution. Incubation can involve activities like sleeping on the problem, taking a break, or engaging in low-level cognitive tasks. Researchers have found that incubation can lead to more effective problem solving, as it allows for selective forgetting and problem restructuring, which can offer a new perspective on the problem and facilitate the discovery of solutions.