The profits will be equally divided . . . . . . . . the two partners

Option A: in
The preposition "in" is not suitable in this context. "In" typically indicates location or position within something, which does not apply to dividing profits.

Option B: into
The preposition "into" suggests movement or transformation, such as dividing something into parts. However, it does not fit well with the concept of distribution among people.

Option C: between
The preposition "between" is correct here because it is used when referring to a distribution involving two distinct entities. Since the sentence mentions "the two partners," "between" accurately describes the equal division of profits.

Option D: among
The preposition "among" is used when referring to distribution involving more than two entities. In this context, it would be incorrect since the sentence specifies two partners.

Conclusion
The correct preposition is "between" because it appropriately describes the division of profits among the two partners.