Following numerous researchers in taking I(nfl) to be the head of a sentence, I assume that it too is projected according to (1)c. The specifier of IP is the canonical position for the subject in English and its presence is motivated by something like the Extended Projection Principle (Chomsky 198 1) or a strong D-feature of inflection (Chomsky 1993). This yields (2) as the scheme for an English clause.