Which word in the sentence, if any, should be followed by a comma?

nevertheless he remains determined to finish the project before the end of the month.

a. nevertheless

b. project

c. determined

d. there is no error in comma usage.

my dad purchased natural colorings in a specialty store

answer: the tobacco industry has traditionally been one of the most important industries in north carolina and a backbone of the state's agricultural heritage. yet as the north carolina economy continues to transition from an agricultural economy to a manufacturing and, increasingly, service-based economy, the industry faces new challenges, both at home and abroad

explanation: