3. The negation of the proposition ``$\exists x _ { 0 } \in ( 0 , + \infty ) , \ln x _ { 0 } = x _ { 0 } - 1$'' is
A. $\forall x \in ( 0 , + \infty ) , \ln x \neq x - 1$
B. $\forall x \notin ( 0 , + \infty ) , \ln x = x - 1$
C. $\exists x _ { 0 } \in ( 0 , + \infty ) , \ln x _ { 0 } \neq x _ { 0 } - 1$
D. $\exists x _ { 0 } \notin ( 0 , + \infty ) , \ln x _ { 0 } = x _ { 0 } - 1$