Because bamboo products require a significant amount of treatment to enable them to withstand sunshine and moisture and many coatings of waxes, resins, and bleaches to stave off termites and decay, manufacturing process of these products is very labor-intensive, crude, and small scale.
(A) bleaches to stave off termites and decay, manufacturing process of these products is
(B) bleaches, staving off termites and decay, leading to manufacturing process of these products being
(C) bleaches, staving off termites and decay, making the manufacturing process of these products
(D) bleaches to stave off termites and decay, and therefore manufacturing and processing of these products become
(E) bleaches to stave off termites and decay so that manufacture and processing of these products are
A No issues,
Correct B main sentence or effect is missing; also it has modifier issue
C same as B
D because and therefore cant be present in same sentence
E same as D - Because and so that