What angles do deviations from rutherford formula begin to occur?

Rutherford and his colleagues were able to calculate the number of alpha particles which would be scattered onto any angle. And with the agreement of these calculations up to a certain large angle where they got significant deviations.

The answer is b because a,c,and d are opinons

Naoh + hbr -> nabr (salt) + h2o ca (oh)2 + 2hbr - - - > ca (br)2 + 2h2o