Final answer:
When the lone pairs are equatorial, there are no 90° LP-LP interactions and four 90° LP-BP interactions, making the total number of 90° interactions at the equatorial site four.
Step-by-step explanation:
The question is asking about the number of 90° interactions (either lone pair-lone pair (LP-LP) or lone pair-bond pair (LP-BP)) at an equatorial site in a molecular geometry. According to the provided information, when the lone pairs are positioned equatorially, there are zero 90° LP-LP interactions and four 90° LP-BP interactions. Therefore, the correct answer to the question, 'The equatorial site has how many 90° interactions?' would be D) 4.