When constructing a heap using an array structure, the left child index and the right child index of the node at index i are given by the formulas

Question $9$ options:

Left child at index $(2$i $-1),$ right child at index $(2$i $+1)$

Left child at index $($i $+1),$ right child at index $($i$+2)$

Left child at index $(2$i $+1),$ right child at index $(3$i$+1)$

Left child at index $(2$i $+1),$ right child at index $(2$i$+2)$