A. proving less restraints
B. increasing span
C. increasing depth of beam
D. decreasing depth of beam
This question was addressed to me in an online quiz.
This is a very interesting question from Deflection & Holes in Beams topic in section Design of Beams of Design of Steel Structures
To explain I would say: Deflection can be reduced by increasing depth of beam, reducing the span, providing greater end restraints or by other means such as providing camber.