Of the Enumeration Below, Which Is Not a Limitation of Fideicommissary

Of the enumeration below, which is not a limitation of fideicommissary substitution?

A) The substitution must not go beyond one degree from the heir originally instituted (Art. 863, NCC) .
B) The fiduciary and the fideicommissary must be living at the time of the death of the testator (Art. 863) .
C) The substitution can burden the legitime (Art. 864) .
D) The substitution must be made expressly (Art. 865) .