Final answer:
In a trigonal bipyramidal molecular shape, when lone pairs are positioned equatorially, there are three 120° interactions among the equatorial bonding pairs.
Step-by-step explanation:
The question seems to be referencing molecular geometry, specifically the arrangement of lone pairs (LP) and bonding pairs (BP) in certain molecular shapes such as trigonal bipyramidal. In a molecule with equatorial lone pairs, there are three 120° interactions between the bonding pairs in the equatorial plane. The 120° LP-BP and BP-BP interactions only occur in this plane, which is why there are multiple 120° interactions.
When lone pairs are positioned equatorially, there are no 90° LP-LP interactions, and there are four 90° LP-BP interactions. However, as the question specifically asks about the 120° interactions, you can infer that there will be three such interactions among the equatorial bonding pairs, thus the correct answer is C) 3.