If the price of aluminum rises, what happens to the steel producer's supply curve? The supply curve:

A. shifts to the left.

B. shifts to the right.

C. remains unchanged.

A producer's supply function is given by the equation:

\[
Q_{s}^{s}=-55+26 P_{s}+1.3 P_{a}
\]

where \(Q_{s}^{s}\) is the quantity of steel supplied by the market, \(P_{s}\) is the per-unit price of steel, and \(P_{a}\) is the per-unit price of aluminum.