A：The data shows that there are three types of palm oil mill machines that are more popular in Nigeria: complete palm oil production lines, simple palm oil pressing lines, and specialized palm oil pressing machines.

A：To save palm oil production costs, you can reduce raw materials costs, palm oil production plant construction cost, palm oil production line purchase cost and the palm oil production cost.

A：The costs involved in building a palm oil plant include palm oil plant construction cost, palm oil processing plant cost, labor cost, palm oil processing plant maintenance cost, waste management cost, personnel training cost, and transportation cost.

A：The development trends and technological innovations in the palm oil making industry include planting palm fruit trees sustainably, improving palm oil making efficiency and palm oil making waste management, etc.