ow does adding children in QObject differ from the classic Composite pattern?

a$.$

Children are automatically added through the $`$setParent$()`$ function without the need for a dedicated $`$addChild$()`$ function.

b$.$

Children are added manually using an $`$addChild$()`$ function as in the classic pattern.

c$.$

Children must be added in the constructor of the QObject.

d$.$

Children are added using a factory method in QObject.