Correct option is C
The correct indirect speech is "The solicitor suggested that they should solve the dispute over the land."
Rules for conversion from direct to indirect speech:
1. "Let us" is used for making a suggestion. In indirect speech, it is converted into "suggested that".
2. The subject pronoun "we" changes to "they", based on the reporting verb.
3. The reporting verb "said" changes to "suggested".
4. The verb "should" is used to maintain the suggestion tone.
Example:
· Direct: He said, “Let us discuss the matter.”
· Indirect: He suggested that they should discuss the matter.