Final answer:
The stomach's muscularis has three layers of smooth muscle, while the muscularis of most of the digestive tract has two layers (option c).
Step-by-step explanation:
The muscularis of the stomach consists of three layers of muscle. These include an inner oblique layer, a middle circular layer, and an outer longitudinal layer. The addition of the inner oblique layer helps the stomach with its vigorous churning and mixing of food. On the other hand, the muscularis of the majority of the digestive tract, like the small intestine and colon, typically consists of two layers of smooth muscle: the inner circular layer and the outer longitudinal layer, with some modifications in certain regions.
Therefore, the correct answer is c) Stomach: 3 layers; Digestive tract: 2 layers.