Neil brags about his five-year-old son's recent achievement in fine motor skills. Neil's son has most likely begun to do which of the following?

Riding a tricycle generally develops earlier, around the ages of 3 to 4, as it primarily involves gross motor skills rather than the fine motor skills that Neil's son is demonstrating. Therefore, while riding a tricycle is a notable achievement, it does not specifically relate to his fine motor skills.

Hopping on one foot is a gross motor skill that typically develops around ages 3 to 4 as well. This skill involves balance and coordination but does not reflect the fine motor skills that are being discussed in Neil's bragging about his son's recent achievements.

While the pincer grasp is an important fine motor skill, it is usually mastered much earlier, around 12 months of age. By age five, children have typically refined their fine motor skills well beyond this initial stage, making this option less relevant to the current context.

Building a tower with ten blocks demonstrates fine motor skills, but this skill is typically developed by the age of 3 to 4. By age five, children can perform more complex tasks, such as tying their shoes, which indicates a more advanced level of fine motor proficiency.