Select the correct indirect form of the given sentence.

The visitor enquired, "When is the next train?"

The visitor enquired when the next train was.

The correct indirect form of the given sentence is:

The visitor enquired when the next train was.

The other options are incorrect for the following reasons:

• The visitor enquired about the next train. This is too general. It does not convey the fact that the visitor asked a specific question about the time of the next train.
• The visitor asked when is the next train. This is a direct quote of the visitor's question. In indirect speech, the question is reported as a statement.
• The visitor was interested in the next train. This sentence does not convey the fact that the visitor asked a question. It simply states that the visitor was interested in the next train.