Sentence Correction

The owners of a fast growing tech start-up in Newport Beach organized the firm as a Limited Liability Company (LLC). The owners receive considerable personal liability protection from potential lawsuits, and they also avoid some egregious double-taxation that would occur if the company was set up as a C-corporation.
A) protection from potential lawsuits, and they also avoid some egregious double-taxation that would occur if the company was set up as a C-corporation
B) protection from potential lawsuits and avoid some egregious double-taxation that would occur if the company was set up as a C-corporation
C) protection from potential lawsuits, avoiding some egregious double-taxation that would occur if the company was set up as a C-corporation
D) protection from potential lawsuits, and avoid some egregious double-taxation that would occur if the company were set up as a C-corporation
E) protection from potential lawsuits and avoid some egregious double-taxation that would occur if the company were set up as a C-corporation

is it true that and after is always wrong, if not then what is the issue with D