Water flows through a constriction in horizontal pipe as it enters constriction, water's:

Explanation

In fluid dynamics, especially in incompressible flow through a pipe, Bernoulli's principle applies. When water flows through a constriction in a horizontal pipe, the cross-sectional area decreases, causing the speed of the water to increase. According to Bernoulli's equation, an increase in fluid speed results in a decrease in pressure. Therefore, option C is correct. Option A is incorrect because pressure does not remain constant; it decreases. Option B is incorrect because it suggests that pressure increases, which is contrary to Bernoulli's principle. Option D is incorrect because it describes the opposite scenario-exiting a constriction.