Select the correct indirect form of the given sentence.
He said to his friend, “Let us leave for the trek tomorrow.”

Correct option is D

He suggested to his friend that they should leave for the trek the next day.
Direct speech- Direct speech, also known as quoted speech or direct quotation, is a way of reporting someone's exact words.
Indirect speech- Indirect speech, also known as reported speech or indirect quotation, is a way of reporting someone's words or thoughts indirectly, without using their exact words.
The direct speech is an imperative sentence, "Let us leave for the trek tomorrow."
In indirect speech, it becomes a suggestion using "should," indicating a proposal or recommendation for future action and “tomorrow” changes to “the next day”.