Answer:
In this scenario, the green light is a(n) <u><em>signal</em></u>.
Explanation:
In the above scenario, with time, the pigeon has learnt that he will be rewarded only when the green light is on. Such a condition is known as learned behaviour. In the future, the pigeon will only peck the button when the green light is on because he will know that he will be rewarded for pecking the button only when the green light is on. Hence, the green light is the signal for the pigeon to start pecking the button.
The question only makes sense if you specify that
you're talking about the same amount of each.
Olive oil . . . . . 120 calories / Tablespoon
Table sugar . . . 22.5 calories / Tablespoon
In equal volumes, olive oil has a little more than
5 times the calories of granulated sugar.
Sesame oil, soybean oil, almond oil, canola oil, corm oil,
cottonseed oil, flaxseed oil, grapeseed oil, palm oil,
macadamia nut oil, peanut oil, safflower oil, walnut oil,
wheatgerm oil, and sunflower oil are all virtually identical
to olive oil in calorie content, but their saturated fat content
is different.
I would say A. The three other choices could lead to its start.