Determine Whether the Given Argument Is Valid or Invalid D) Invalid

Multiple Choice

determine whether the given argument is valid or invalid. If it is invalid, select a counterexample.
-1. (?x) [Tx ? (?y) (Sy • Wxy) ]
2) (?x) (Sx • Vx)
3) (?x) (Tx • Rx) / (?x) [(Rx • Vx) • (?y) Wxy]

A) Valid
B) Invalid. Counterexample in a domain of one member, in which: Ta: True Sa: False Waa: True
Ra: False Va: True
C) Invalid. Counterexample in a domain of two members, in which:
$\begin{array}{lll}\text { Ta: False } & \text { Sa: False } & \text { Waa: True } \\\text { Tb: True } & \text { Sb: True } & \text { Wab: False } \\\text { Ra: True } & \text { Va: False } & \text { Wba: False } \\\text { Rb: False } & \text { Vb: False } & \text { Wbb:True }\end{array}$

D) Invalid. Counterexample in a domain of two members, in which:
$\begin{array}{lll}\text { Ta: False } & \text { Sa: True } & \text { Waa: True } \\\text { Tb: True } & \text { Sb: True } & \text { Wab: True } \\\text { Ra: False } & \text { Va: False } & \text { Wba: False } \\\text { Rb: False } & \text { Vb:True } & \text { Wbb: False }\end{array}$

E) Invalid. Counterexample in a domain of two members, in which:
$\begin{array}{llll}\text { Ta: True } & \text { Sa: True } & \text { Waa: True } & \\ \text { Tb: False } & \text { Sb: True } & \text { Wab: True } \\ \text { Ra: True } & \text { Va: False } & \text { Wba: True } \\\text { Rb: False } & \text { Vb:True } & \text { Wbb: True }\end{array}$