English grammar related to prepositions

You have made a query regarding the correct preposition for the blank in the given sentence. I would suggest you to put among in the blank space. Between would not be correct since there should have two nouns connecting between two nouns.
Take the following sentence as example-
1) There is no difference between Ram and Shyam in relation to their intelligence.
2) Binoy is the most intelligent among the group of forty boys.
Hope, you have got your answer.

Between is used when there are two object. Whereas among is used when there are three or more objects. Between preposition specifically refers to the condition of being in the middle of two and exactly two things. One on each side. Think about something being 'sandwiched' between, or caught in between, two other things.
"Among" refers specifically to the condition of being in the midst of three or more and no less than three things. Here are some examples:-
You can sit between your parents, but you can't sit among them. As question asked by you, what would be correct preposition in given sentences. I think answer must have cleared by our examples. Your correct answer would be 'among' for given sentences.

when there are two types of fruits and one type you have to select, you will be asked to choose one between the two types of fruits available there. If there are more varieties of fruits and you have to choose one, you will be asked to choose one among the available fruits there. I think you understood the way. However, this can be defined as below.
Generally among will be used when something is in or with a group of a few, several, or many things. and between will be used when something is in the middle of two things or two groups of things.
Based on the above facts, the dash in your question has to be filled with "among"