Final answer:
The correct expression that formalizes the given reasoning is ¬ (∀x) (Ix → ( Lx ˄ Fx ))
Step-by-step explanation:
The correct expression that formalizes the given reasoning is d. ¬ (∀x) (Ix → ( Lx ˄ Fx )). This expression represents the negation of the statement that for all computer scientists (Ix), if they know logic (Lx), then they program in Fortran (Fx). By using the negation operator (∼) and the universal quantifier (∀), we can accurately represent the given reasoning.