Which of the Following Is the Existential Instantiation Rule?
A)(x) $\exists$

Which of the following is the existential instantiation rule?

A) (x) ( ...x ...) .Therefore, ( ...a ...)
B) ~(x) ( ...x ...) .Therefore, ( $\exists$ x) ~( ...x ...)
C) ( ...a ...) .Therefore, ( $\exists$ x) ( ...x ...)
D) ( $\exists$ x) ( ...x ...) .Therefore, ( ...a ...)
E) ( ...a ...) .Therefore, (x) ( ...x ...)