Small business owners play important roles in a community, providing products from local manufacturers, independent craftsman as well as international artists; they hire both older and younger workers; and occasionally bring new life to dilapidated shopping centers.
A)
they hire both older and younger workers and occasionally bring
This sounds very promising at first glance.
There is a semicolon, which can rightly connect two independent clauses without a conjunction, but we encounter pronoun ambiguity. "They" can refer back to local manufacturers, craftsmen, artists, and business owners. B)
it hires both older and younger workers and occasionally brings
"IT" is wrong. Can't refer back to small business owners C)
hiring both older and younger workers; and occasionally
bringWrong parallelism - "Hiring" and "Bring" are not in parallel D) hiring both older and younger workers; and occasionally bringing
Correct - Please not that a semicolon can also function as a super comma.
E)
they are hiring both older and younger workers and occasionally bringing
Who are "They" - Same problem as A