Correct Answer: My friend Ganesh said that he could solve the biggest problem very easily.

Solution : The correct choice is the fourth option .

Indirect speech is speech that tells you what someone said but does not use the person's actual words. In indirect speech, when reporting someone else's statement, we often shift the pronouns and verb tenses.

The steps of conversion are as follows:

• The pronoun "I" in the direct speech is changed to "he" in the indirect speech to reflect the perspective of the speaker in the reporting sentence.
• The verb "could" remains the same because it is reporting a past ability, and there is no need to change it.
• The reporting verb "said" is used to introduce the reported statement.
• The connector "that" is used to introduce the reported clause.

Therefore, the correct answer is: My friend Ganesh said that he could solve the biggest problem very easily.