A sentence is provided in direct speech. From the four given options, choose the one that most accurately conveys the sentence in its corresponding indirect speech. I said, “Let us start early.”

Correct — C. Let us proposes an action to a group that includes the speaker, so it is reported as a suggestion: suggested (or proposed).

A reported suggestion takes that + subject + should + base verb.
Us, the group, becomes the subject of that clause, so it turns into we. The reporter is the speaker, so first person stays first person.

Result: 'I suggested that we should start early.' → option (c).

Why the others are wrong

• (a)
  I said let us start early. — I said let us start early only removes the quotation marks. The proposal let us is still there, so nothing has been turned into reported speech.
• (b)
  I told that we must start early. — Told needs the person told after it, as in 'told them that'. And must turns a suggestion into an obligation the speaker never stated.
• (d)
  I suggested us to start early. — Suggested us to start gives suggest an object and a to-infinitive. Suggest is built with a that-clause, often with should, or an -ing form ('I suggested starting early'), and this is neither.

Let's, or its formal form let us, is how English proposes an action to a group that includes the speaker. Wiktionary calls it the cohortative: in effect a first-person plural imperative.

Reported, it is named for what it does. The reporting verb becomes suggested or proposed, and the clause takes that + subject + should + base verb.

Pronouns follow the reporter: here the reporter is I, the speaker, so us becomes we.

Key facts

• Let's (formal: let us) proposes an action to a group that includes the speaker.
• A reported suggestion: suggest or propose + that + subject + should + base verb.
• Suggest also takes an -ing form: I suggested starting early.
• Tell names its listener (told them that). Say does not (said that).

Common traps

• Choosing (d) because suggested looks right, without checking the pattern that follows it.
• Copying let us into the reported sentence, which only removes the quotation marks.

No directly related past PYQ was found.