Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Brown core of apple develops in the fruit at the time of fruit set
Reason (R) : Brown core is a low storage problem developing in fruits at -1$^\circ$C to 2$^\circ$C
In light of the above statements, choose the most appropriate answer from the options given below.