$$13$$、$$10$$、$$31$$、$$30$$， notice that $$0$$ cannot be in the first place, so only $$4$$ numbers can be formed．  So the answer is $$\text{B}$$． 
We can formdifferent two-digit numbers with the numbers $$1$$, $$3$$ and $$0$$.（without using the same number two times like $$33$$ ） 

[a] $$3$$ 
[b] $$4$$ 
[c] $$5$$ 
[d] $$6$$ 