Which description best explains the mechanism for the reaction shown?

◦ Br
- leaves, producing a carbocation. A rearrangement occurs, allowing SH
- to add to the bottom vertex.
◦ SH
- is added, which forces Br
- to leave. This allows rearrangement to take place.
◦ Rearrangement occurs, forcing Br
- to leave. This allows SH
- to add to the bottom vertex.
◦ Br
- leaves, producing a carbocation. A rearrangement occurs, allowing SH
- to add to the bottom vertex of the ring.
◦ Br
- leaves and SH
- is added simultaneously, then a rearrangement occurs.