14. let f: r2- r be defined by fx.y)=*+y, if x and y are irrationals 0, otherwise then (a) f is not continuous at (0, 0) t is continuous at (0, 0) but not diffe

14. Let f: R2- R be defined by fx.y)=*+Y, if x and y are irrationals 0, otherwise Then (A) f is not continuous at (0, 0) T is continuous at (0, 0) but not differentiable at (0, 0) (C) fis differentiable only at (0, 0) (P) fis differentiable everywhere (B)