Hi
The answer is option 2: when a couple is dancing on the floor and a single man comes up and asks to dance with the woman. Then the woman starts dancing with a new partner and the original man is all alone.
Explanation:
Single-replacement reaction or single displacement reactions are a type of chemical reactions in which a whole compound reacts with an element in such a way that the element takes place of one of the compound's own elements and sets it free.
For example:
KBr + I -> K + IBr
Potassium Bromide + Iodine -> Iodine(i) Bromide +Potassium
It is a very common reaction in which iodine reacts with potassium bromide and replaces the place of bromine of potassium bromide. Therefore it is called as single displacement reaction.
Hope it help!