Which group of elements could be placed in Mendeleev's Periodic Table without disturbing the original order? Give reason.

(A) The group of elements that could be placed in Mendeleev's Periodic Table without disturbing the original order is the Noble gases.
Reason:
$1$. Mendeleev's periodic law states that the properties of elements are a periodic function of their atomic masses.
$2$. Noble gases are chemically inert and possess very low reactivity due to their stable electronic configuration.
$3$. Because they do not react with other elements,they could be placed in a separate group (Group $0$ or $VIII$) without requiring any changes to the positions of the existing elements in the table.