The correct answer is C. stabilizing; a tall, narrow peak in the center of the graph.
In this scenario, medium brown fur provides a selective advantage over both light brown and dark brown fur. This type of selection, where individuals with intermediate traits have a higher fitness than individuals with extreme traits, is known as stabilizing selection.
In a population undergoing stabilizing selection, the distribution curve would show a tall, narrow peak in the center of the graph. This indicates that the majority of individuals possess the trait that provides the highest fitness (medium brown fur, in this case), while individuals with extreme traits (light brown and dark brown fur) are gradually eliminated from the population.