Concept:
Dacoity is defined under Section 391 of the Indian Penal Code (IPC). It is an aggravated form of robbery involving multiple persons.
Step 1: Definition under IPC.
According to Section 391 IPC, when five or more persons conjointly commit or attempt to commit robbery, it is called dacoity.
Step 2: Minimum requirement.
The law clearly specifies that the minimum number of persons required is five.
Step 3: Eliminating other options.
Any number less than five will not amount to dacoity; it may constitute robbery but not dacoity.