This was a very popular question among the candidates however, most respondent candidates were only able to state only one of the factors (speed of projection) while majority left out the second factor (time of flight).  Some clever candidates list more than two factors expecting the examiner to pick the correct two for them.  Among the factors listed are:  speed/velocity, angle of projection, acceleration due to gravity “g” height of the building, time of flight.  Candidates just need recall the formula for horizontal range  R  =  Uxt.
          The expected answer  is

•    Its initial speed
•    Time (of flight)