From the following statements which of them is/are true about SQL1. All attributes used in the group by clause must appear in the select clause2. An SQL query can contain a having clause only if it has a group by clause3. An SQL query can contain a having clause even if it does not have a group by clause4. Not all attributes used in the group by clause need to appear in the select clause

• A. 3 and 4
• B. 1 and 2
• C. 1,3 and 4
• D. All of the above