Select the best translation into predicate logic, using the following translation key:

a: true

b: false

p: Proposition P

q: Proposition Q

f(x): the truth-value of x

g(x): the truth value of ‘~x’

f(x,y): the truth value of ‘x ⊃ y’

g(x,y): the truth value of ‘x ≡ y’

Px: x is a proposition