D is the only choice here that is appropriate given neutrons' lack of charge
The balanced equation of the reaction is:
O3(g) + NO (g) → O2 (g) + NO2 (g)
Then the ratios of reaction is 1 mol O3 : 1 mol NO : 1 mol O2 : 1 mol NO2
If you have initially 0.05 M of O3 and 0.02 M of NO, the reaction will end when all the NO is consumed.
The by the stoichiometry 0.02 mol of O3 will be consumed in 8 seconds.
And the rate of reaction is change in concetration divided by the time.
The change in concentration in O3 is 0.02 M
Then, the rate respect O3 is 0.02 M / 8 seconds = 0.0025 M/s
Potassium hydroxide is a strong base and hydrobromic acid is a strong acid. This implies that the pH of the end-point [neutralization] of their titration will be around pH 7. A good indicator for this kind of pH is bromthymol blue. This is because this indicator changes its colour at pH 7.
The most stable isotope would be lead-82.
