Answer
For all 4 products, in the 1st step, Br leaves. For the 4-membered ring E1 product, HOCH3 deprotonates an adjacent carbon to form a double bond. For the 4-membered ring SN1 product, a hydride shift occurs before HOCH3 attacks carbocation and undergo deprotonation. For the 5-membered ring products, a methyl shift happens to form the pentane. Then, the ring undergoes similar mechanism as E1 and SN1 for the 4-membered rings correspondingly.
Work Step by Step
See image.
