**The reasoning**
The key principle here is **pronoun case after prepositions**. Words like "between," "with," "for," "to," and "from" are prepositions, and they must be followed by **object pronouns**, not subject pronouns.
Subject pronouns: I, we, he, she, they
Object pronouns: me, us, him, her, them
Since "between" is a preposition, you need the object form. So it's "between you and **me**" — not "between you and I."
A simple test: Remove the other person. You'd say "between me" not "between I," right? Same logic applies when you add someone else.
**Why the wrong options tempt you**
- **A (between you and I)**: This sounds "polite" or "proper" to many people, but it's grammatically wrong. "I" is a subject pronoun; after "between," you need "me."
- **C (between we)**: "We" is also a subject pronoun. Sounds obviously wrong when isolated.
- **D (between us and they)**: "They" is subject form; should be "us and them."
**Quick takeaway**
After prepositions like "between," always use object pronouns: me, us, him, her, them — never I, we, he, she, they.