Which of the Following Is Not a Condition for a Symbolic

Multiple Choice

Which of the following is not a condition for a symbolic expression to be a well-formed formula (WFF) ?

A) If p is a WFF, then so is ~(p) .
B) If p and q are WFFs, then so is (p • q) .
C) If p and q are WFFs, then so is (p ⋁ q) .
D) If p and q are WFFs, then so is (p → q) .