Which statement most accurately summarizes the licensing rule a contractor must satisfy to recover compensation in a lawsuit over a construction contract?

Explanation

§7031(a) bars any person engaged in the business or acting in the capacity of a contractor from bringing or maintaining an action to collect compensation for work requiring a licence without alleging that they were a duly licensed contractor at all times during the performance of that act or contract, and it says so expressly regardless of the merits of the cause of action. The moment that matters is therefore the whole period of performance, not the filing date in (a) or the payment date in (c). §7031(d) adds how it is proved once licensure is controverted: a verified certificate of licensure from the board establishing proper licensure throughout. §7031(b) is the mirror image and the reason good work cannot save (d) — the person who used an unlicensed contractor may sue to recover all compensation already paid, however well the job was done. The one carve-out §7031(a) names is for contractors each individually licensed who fail to comply with §7029's joint venture licence.