Following observation were recorded upon performing experiments with sample 'A' and sample 'B'. (i) When 2-3 drops of phenolphthalein are added to sample 'A' it becomes pink. (ii) When equal quantities of two samples are added in a test-tube, the test-tube becomes hot.

• A. sample 'A' is basic      
• B. sample 'B' is acidic
• C. (ii) observation confirms neutralisation
• D. All the above are correct