Add a method you your car class that takes another car object as a parameter and then compares the wheel size, something like this:
public class Car
{
public int WheelSize { get; set; }
public IsWheelSizeEqual(Car otherCar)
{
bool result = false;
if (otherCar != null)
{
result = (this.WheelSize == otherCar.WheelSize);
}
return result;
}
}
You could make the method a lot more useful is you used reflection and allowed the calling method to specify which property to compare for equality.
You could also write an extension method which would compare all properties in the two car objects for equality.
I suspect the last two ideas above would far exceed what your instructor expects from a beginner C# programmer...