In the experiment conducted by Griffith when a mixture of heat killed S-strain and live R-strain of Pneumococcus bacteria was injected into a healthy mice, it developed pneumonia. This was due to
1. Reactivation of S-strain bacteria
2. Transformation of S-strain bacteria into R-strain bacteria
3. Synthesis of polysaccharide coat around heat killed S-strain bacteria
4. Transformed R-strain bacteria