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) \( (x) [(T x \cup D x) \supset F x] \) } & \text {\(I(x) (\mathrm{D} x \supset \mathrm{F} x) \) }& \text { Premise/Conclusion } \\ \text { (2) \( \mathrm{Da} \) } && \text { Assumption}\\ \text { (3) \( (\mathrm{Ta} \vee \mathrm{Da}) \supset \mathrm{Fa} \) } && \text { \( 1 \mathrm{UI} \) }\\ \text {(4) \( \mathrm{Ta} \cup \mathrm{Da} \) } &\\\end{array}$

A) 1 UI
B) 3 Simp
C) 2 Add
D) 2, 3 MT
E) None of these answers are correct.