The guard cell of the stomata in Monocot is:

Explanation

The correct answer is dumbbell-shaped. Monocots have stomatal guard cells that are dumbbell-shaped, allowing for better regulation of gas exchange. This shape is better suited for monocots, which often grow in environments where water conservation is critical. In contrast, dicots usually have kidney-shaped guard cells, which are adapted to their specific environmental conditions. The other options, such as kidney, oval, and rounded shapes, do not accurately represent the typical guard cell shape found in monocots.