Propose a mechanism for each reaction, showing explicitly how the observed mixtures of products are formed. (a)

Question:

Propose a mechanism for each reaction, showing explicitly how the observed mixtures of products are formed.
(a) 3-methylbut-2-en-1-ol + HBr → 1-bromo-3-methylbut-2-ene + 3-bromo-3-methylbut-1-ene
(b) 2-methylbut-3-en-2-ol + HBr → 1-bromo-3-methylbut-2-ene + 3-bromo-3-methylbut-1-ene
(c) cyclopenta-1, 3-diene + Br2 → 3, 4-dibromocyclopent-1-ene + 3, 5-dibromocyclopent-1-ene
(d) 1-chlorobut-2-ene + AgNO3, H2O → but-2-en-1-ol + but-3-en-2-ol
(e) 3-chlorobut-1-ene + AgNO3, H2O → but-2-en-1-ol + but-3-en-2-ol