Final answer:
A command or request ends with a period when expressed without strong emotion and with an exclamation mark when strong feelings or urgency are conveyed.
Step-by-step explanation:
A command or request can end with a period or an exclamation mark. When a command is given in a normal tone without much emotion, a period is used at the end. For example:
“Do not attempt to drive to school this morning.”
However, if the command is meant to convey strong feelings or urgency, an exclamation mark is used. For example:
“Stop! That hurts!” he shouted.
Therefore, the correct answers to the question of what makes a request or command end with a period or an exclamation are options 3) A period and 4) An exclamation mark.