Which of these architects developed the st. peter’s basilica that exists today, and what were his changes from the original design? a. bramante rebuilt it with a central-plan design. b. michelangelo developed it with unified space and a spherical dome. c. carlo maderno extended the nave to 636 feet, and added a new facade.

I believe the correct answer is C. Carlo Maderno extended the nave to 636 feet, and added a new facade.

The Pope Paul V had appointed Carlo Maderno in 1602. to be in charge of rebuilding Saint Peter’s basilica.  Maderno's idea was to modify Michelangelo's building plans and provide designs for an extended nave with a palatial facade. Maderno extended the single bay of Michelangelo's Greek Cross (the nave) by adding a further three bays. He made the dimensions slightly different from Michelangelo's bay (extended by 636 feet), thus defining where the two architectural works meet.  Madern’s facade is 376.3 feet wide and 149.4 feet high, built of travertine stone, with a giant order of Corinthian columns. In the central pediment rising in front of a tall attic surmounted by thirteen statues: Christ flanked by eleven of the Apostles (except Saint Peter) and John the Baptist.

c

Explanation:

the previous answer given.