Discover the best answers at Westonci.ca, where experts share their insights and knowledge with you. Get quick and reliable answers to your questions from a dedicated community of professionals on our platform. Connect with a community of professionals ready to provide precise solutions to your questions quickly and accurately.

Which sentence is written correctly?
a. He has had several years' experience, and is thoroughly competent.
b. He has had several years' experience; and is thoroughly competent.
c. He has had several years' experience and is thoroughly competent.
d. He has had several years' experience and, is thoroughly competent.