In which of the following systems would a child's school relationships belong?

The correct answer is that a child's school relationships belong in the mesosystem. The mesosystem encompasses the interconnections between different microsystems in a child's life, such as the relationships and interactions between home, school, and peer groups. These relationships are significant because they involve direct interactions that influence the child’s development and well-being.

In the context of a child, school relationships directly affect their social skills, academic performance, and overall emotional health. The support and challenges a child encounters at school can have a profound effect on how they relate to their family and peers outside of school, making the mesosystem a critical component of understanding a child's social environment.

Other options, like the exosystem, refer to the broader social systems that indirectly influence the child, such as parental workplaces or community services. The macrosystem involves overarching cultural influences and societal norms, while the chronosystem focuses on the dimension of time and the changes that occur throughout a person's life. None of these options directly address the specific, interconnected relationships within the child's immediate environment like the mesosystem does.