给出下列代码: class?Plane?{ static?String?s?=?"-"; public?static?void?main(String[]?args){ new?Plane().s1(); System.out.println(s); } void?s1()?{ try?{s2();}catch?(Exception?e){ ?s?+=?"c";? } } void?s2()?throws?Exception?{ s3();? s?+=?"2"; s3(); s?+=?"2b"; } void?s3()?throws?Exception{ throw?new?Exception(); } } 结果是什么?
A.-
B.-c
C.-c2
D.-2c