Is the application of corporate governance codes throughout the member states more or less harmonised?

The way of applying differs across EU because of the different paths taken by the member states.

Some EU countries local listing rules refer to the local code to be applicable: means the rules refer to the code.

In some states listing rules need to specify that the code needs to be applied because the code itself mentions it: means the code refers to which corporation must apply the code.

Only A and B are correct.

A, B, C are all correct.