Correct option is B. $$2/3$$
$$1, \,2, \,3, \,4, \,6, \,8, \,12, \,24$$ are the factors of $$24$$
$$1, \,2, \,3, \,4, \,6, \,9, \,12, \,18, \,36$$ are the factors of $$36$$
Common factors of $$24$$ and $$36$$ are $$1, \,2, \,3, \,4, \,6$$ and $$12$$
$$HCF \,= \,12$$
Now dividing both numerator and denominator by $$12$$
$$=24\div12/36\div12$$
$$=2/3$$
Thus $$2/3$$ is the equivalent factor to $$24/36$$.