Project Management Approach:

For this project, I would opt for a responsive and adaptable style of project management. Here's my reasoning:

a$.$ Start$-$Up Environment: Startups often operate in highly dynamic and uncertain environments. A responsive and adaptable style of project management allows for quick adjustments in response to changing circumstances, market conditions, and customer feedback.

b$.$ Small Team: With a small development team, a command and control style may stifle creativity and hinder the team's ability to adapt to evolving requirements. A more responsive approach encourages team collaboration and innovation.

c$.$ Customer$-$Centric Focus: In a startup, customer satisfaction and product$-$market fit are paramount. A responsive approach that incorporates customer feedback and adapts accordingly is better aligned with these objectives.

In summary, the chosen project, the development of a CRM software for a startup, would have been better suited to an agile project management approach due to its changing requirements, small team, and customer$-$centric nature. The advantages of agility, such as flexibility and customer satisfaction, align well with the startup's needs, although it may introduce some unpredictability and require a shift towards a responsive and adaptable management style.