In projectile motion the

Explanation

In projectile motion, the only acceleration acting on the object is due to gravity, which acts in the vertical direction. Therefore, the correct statement is that the acceleration is vertical, while the velocity can have both horizontal and vertical components. Option B correctly captures this concept. Option A is incorrect because it suggests that acceleration is always parallel or antiparallel to velocity, which is not true for projectile motion. Option C incorrectly states that acceleration is perpendicular to velocity, which is not a general rule for projectile motion. Option D is misleading because it suggests that velocity only has a horizontal component, ignoring the fact that there can be a vertical component of velocity as well.