The correct option is D All of the above
Alternative Conjunctions: Conjunctions that offers choice between two options are called alternative conjunctions. Example: or, either... or, neither... nor etc.
Option D is correct: "Or", "otherwise" and "else" joins together the given two sentences as alternatives. Hence, they all are alternative conjunctions.
Selecting just one of the given option would leave out the other. Hence, D is the correct answer.