Is word opportunities a object of a preposition?

This depends on the sentence given. Prepositions are words that associate an object to a certain location or position. Examples of prepositions are: on, after, below, by, during, and many more. If you want to use the word 'opportunities' as the object of your preposition, an example would be as follows:

Mary is hopefully praying for good luck as she takes on opportunities. The preposition is 'on' and the object of preposition is 'opportunities'.

can i see the painting?

given the fact that the question is about the detail that best support the idea that oppressive leaders use   propaganda to achieve thir goals,   the first option does not refer to any kind of propaganda, since it only tells about that the milk and the windfall apple should be reserved for the pigs. in the second option, that is, "snowball and napoleon sent out flights of pigeons whose instructions were to mingle with the animals on the neighbouring farms, tell them the story of the rebellion, and teach them the tune of "beasts of england". it can be identified that the oppressors make use of the propaganda, which is represented by the pigeons, and the information they have to tell other animals about what was happening in the farm in order to get their objectives. for that reason, the right answer is the second option, taking into account that the third option do not refer to propaganda since it only talks about that they did not want jones back. and, finally, the last option refers to the result of the given news, but it does not mean about the propaganda they used to achieve their goals.