Is it permitted to enter an intersection in reverse in order to merge into traffic?

A)Yes, if it does not obstruct the circulation of other vehicles.
B)No, because it is forbidden to enter an intersection.Correct
C)Yes, if it does not travel more than 15 metres in reverse.
As a general rule, it is forbidden to drive in reverse, except in the following cases as exceptional and always with the minimum essential distance:

1. As a complementary manoeuvre to stopping, parking or merging into traffic. In this case, the reverse distance may not exceed 15 metres nor enter an intersection.
2. When it is not possible to move forward or to change direction or sense of travel. In this case there is no reverse distance limit, and it is even possible to enter an intersection if necessary.

The reverse manoeuvre is forbidden on motorways and dual carriageways.