Are income distributions from a qualified state tuition program$$ taxable

A mechanic performs work on his own automobile. The mechanic would have charged a customer$$ $$400$ for doing the same work.

b$.$

A mechanic repairs his$$ neighbor's personal automobile. In$$ exchange, the$$ neighbor, an$$ accountant, agrees to prepare the $$ mechanic's tax return. The services performed are each worth$$ $$200.$

c$.$

A mechanic repairs his$$ daughter's automobile without any charge.