Choice "C" is correct. A clear example of an employee is one who works full time for the employer, uses the employer's tools, is compensated on a time basis, and is subject to supervision of the employer in the details of the work. A clear example of an independent contractor is one who has a calling of his own, who uses his own tools, is hired for a particular job, is paid a given amount for the job, and follows his own discretion. Thus, payment on a weekly basis is an indication that a person is an employee rather than an independent contractor.
Choice "b" is incorrect. If Lee's work is not supervised by Sew's personnel, per the above, that would be an indication of independent contractor status.
Choice "d" is incorrect. Per the above, Lee's ownership of his own tools would indicate that he is an independent contractor.
Choice "a" is incorrect. Work that requires a high degree of skill might be considered a calling or might be difficult to supervise. In any case, it would be indicative of independent contractor status.