CMA 695 1-19, which one of the following would cause the demand curve for a commodity (this is a normal good) to shift to the left?

C - A rise in the price of a complementary commodity.
A rise in the price of a complimentary good decreases consumer demand for this good at any price, so the demand curve shifts to the left.
That is, at any price, the demand for the good is now lower.
Since this is a normal good, option B doesn't affect it.
Option A is also not correct because a rise in the price of a substitute product will have the opposite effect: demand for this product will increase at any price level and so the demand curve will shift to the right.
A change in consumer tastes in favor of the commodity (option D) will also shift the demand curve to the right.