If the probability of an event in an experiment is a number r such that
A) 0<r<1 (there is equal sign under the greater sign)
The question is worded badly, the meaning is not clear.
If something has to happen then it has a probabiliy of 1 r=1
If something has to happent is has a probablility of 0 r=0
All other possiblilities are between these extremes. So this would be 0<r<1
If you have no idea what the probable outcome might be then r could be over the whole range of possibilities
\(0\le r \le 1\)
Does this answer your question?