Consumer will increase their current demand for diamonds if consumers expects a rise in future price of diamonds. Hence, the current demand curve will shift to the right.
Producers will decrease their current supply for diamonds if producers expects a rise in the future price of diamonds. Hence, the current supply curve will shift to the left.
In figure F, supply curve shifted to the left and demand curve shifted to the right.
Hence, figure F best describe the change in diamond market if both consumer and producers expects a rise in the future price of the diamonds.
Answer: Figure "F".