Final answer:
Nine actors portrayed the Doctor in 'Doctor Who' before David Tennant, starting from the show's original airing in 1963 up to 2005.
Step-by-step explanation:
Before David Tennant took on the iconic role of the Doctor in the beloved British series Doctor Who, there were nine actors who portrayed the character. These actors, in order of their appearance from the show's inception in 1963 until Tennant began in 2005, are: William Hartnell, Patrick Troughton, Jon Pertwee, Tom Baker, Peter Davison, Colin Baker, Sylvester McCoy, Paul McGann, and Christopher Eccleston. Thus, the correct answer to the question of how many actors played the Doctor before David Tennant is c) 9.