How many solutions that can be expressed with positive integers does the equation below have? ($$1999$$ Math kangaroo Problems, Level $$7-8$$, Question \#$$26$$)  $$a^{2}b-1=1999$$ 
选项为:A:$$3$$  B:$$4$$  C:$$5$$  D:$$6$$  E:$$7$$  请回答其中一个选项.