Chemical transformation refers to the methods which use chemicals in order to carry out transformation. Which of the following statements is true with respect to it?

• A. Chemical transformation decreases the efficiency of transformation as compared to natural transformation
• B. Ice cold calcium solution followed by heat shock is responsible for affecting the efficiency of DNA uptake
• C. The mechanism responsible for it named as ‚Äö√Ñ√∂‚àö√ë‚àö‚â§the heat shock model‚Äö√Ñ√∂‚àö√ë‚àö¬•
• D. Other complex mixtures such as those containing Manganese and hexamine cobalt can‚Äö√Ñ√∂‚àö√ë‚àö¬•t be used to affect the efficiency