in my opinion the answer should be
D- enthusiasm.
Henry Ford first used what was common in other industrial factories in his own. He created a perfect assembly line where a car was manufactured in just under 90 minutes instead of the usual 13 hours. This perfection in manufacturing meant that no time was to go wasted, this meant that workers were a psrt of a single aspect in the assembly line instead of doing 2 or 3 jobs within production. He created a complex system of trolleys and slides that helped with this purpose of maximizing efficiency. The mass production meant that they could sell more cars and keep their prices down and increasing profits at the same time. He created cars not only with mass production in mind but also with mass consumption. Henry Ford wanted everybody to own a car, not just the little upper rich class.
Systematic Observation is a method used to understand how a particular activity or task works. The researcher observes the stages of a process, the tools used, the difficulties that appear, the conversations and the results of the work.
From this method the conclusion is a consequence of the whole process so it is acquired, the whole process of analysis will lead to the conclusion.
