Sally conceives of a zero$-$point gravity machine, which can power cars, air$-$condition homes, and even cities. Can Sally obtain a patent on her idea?

a$.$ Yes, if no one else has developed her idea first.

b$.$ Yes, because she is entitled to intellectual property rights.

c$.$ No$,$ because Sally has not published her idea yet.

d$.$ No$,$ unless she first makes some tangible form of the machine