The ideas of democritus were based on experimenting and testing deductive reasoning speculation inductive reasoning

speculation.

Explanation:

Democritus was a pre-Socratic philosopher. Like all philosophers who share this label, they mostly engaged in a kind of thought governed by speculation in search of governing doctrines, in specific a peculiar form of speculation, that is to say, a kind of informed and well-reasoned imaginative effort based on no empirical or demonstrable principles. One such speculative doctrine is his theory of atoms which holds great resemblance with the modern day conception of atoms that we have today, though they are based on extremely different arguments and, in the case of the Greek philosopher, no observable phenomena.  

light has energy and momentum and so the beams are ever so slightly attracted to each if they had mass. they will ever so slightly curve space.

reference

the answer is c. : )