Which of these most clearly REQUIRES a contractor's license?

解析

B&P §7048(a) exempts a project only where the aggregate price for labor, materials, and all other items is under $1,000, the work is casual, minor, or inconsequential, and no building permit is required, so a $6,000 remodel for a client needs a license. (a) sits under the dollar threshold and is complete in itself — though §7048(b) would withdraw the exemption if it were one slice of a larger job. (b) is the owner working on their own property, which is not contracting for another. (c) is neither construction work nor work done for compensation. Note also §7048(c): the exemption is lost by anyone who advertises as a contractor, or who employs another person to do the work.