output

$ ruby t.rb
[MyClass, D, C, ClassForIncludes, B, A, Object, Kernel, BasicObject]

t.rb

module A
end

module B
end

module C
end

module D
end

class ClassForIncludes
end

class MyClass < ClassForIncludes
  include C
  include D
end

# determine what to include (A, B)

class ClassForIncludes
  include A
  include B
end

p MyClass.ancestors