Please explain why to choose the true answer, and why the other answer is not true, thanks

4. Which of the following circumstances cannot be considered as carrying on a business? (a) Jack and Jill are teachers and they both work 20 hours per week in salaried employment. They live on a 50 acre property and spend around 20 hours per week each farming the property. They incur losses for the first 3 income years in their farming activities before making a modest profit. (b) Wiremu owns a small fishing launch (boat). After he loses his job, he earns income by taking recreational fishers on day trips. He advertises in the local shops, and he takes fishers out on average four days each week His net income after expenses except for depreciation is about $80 per week. He is still looking for further paid employment (c) Dimu is an environmental science lecturer. He also has a keen interest in nature photography. On the weekends, he goes into the bush and photographs birds and vegetation. He often sells his photos to tourists to help pay for his photography costs. (d) Jimbob is a keen gardener. As well as growing vegetables for his own use, he grows sells it regularly each week through the local farmer's market. marijuana using hydroponic equipment , and