In most high schools, precalculus is supposed to be sufficient preparation for calculus (although it may be taught poorly in many high schools so that it actually is not in those high schools).
No one else here knows what you mean by 3A and 3B.
It may also depend on how well the student did in precalculus. If the student barely managed a C- in precalculus, the student may struggle in calculus. But a student who earned an A or B in a well-taught precalculus course should be ready for calculus.