Here it says to pick the best indicator for the following titration. If we take a look at this titration curve, we can see that the steep drop happens around this region in terms of volume, and dead in the middle of that is our equivalence point. Here our equivalence point looks like it's just hovering just below 7.
Now remember the best indicator for titration is when the pKa value of the indicator is close to the pH at the equivalence point. So here are each of the equivalence point is near 7. So what we want an indicator that has a pKa close to seven as well.
If we take a look at look at our options, only option A is close enough to that pH of seven. So here option A where we have bromothymobilume is the correct answer.