Consider a binary heap of n elements in which elements are stored in array from index 1 to n
Parent of any element at index i is calculated as $\lfloor{\frac{i}{2}}\rfloor$
For ex. Index of parent of 2(its index is 8) =$\lfloor{\frac{8}{2}}\rfloor=4$
Index of parent of 3(its index is 7) =$\lfloor{\frac{7}{2}}\rfloor=3$
Hence option 3) is correct