In the Following Proof, Which Justification Is Correct for Line

Multiple Choice

In the following proof, which justification is correct for line 4? $\begin{array}{llcc} \text {(1) \( (x) [(\mathrm{C} x \supset \mathrm{D} x) \supset \sim \mathrm{E} x] \) } && \text { Premise } \\ \text { (2) \( \mathrm{Ea} \) } & \text {\(/ \sim(\mathrm{Ca} \cdot \mathrm{Da}) \) }& \text { Premise/Conclusion}\\ \text { (3) \( \mathrm{Ca} \cdot \mathrm{Da} \) } && \text { Assumption }\\ \text { (4) \( (\mathrm{Ca} \supset \mathrm{Da}) \supset \sim \mathrm{Ea} \) } &\\\end{array}$

A) 1 UI
B) 1 Simp
C) Assumption
D) 3 Add
E) None of these answers are correct.