Select all that apply.

which of the following techniques have been employed to improve the efficiency of fireplaces?
addition of catalytic combustors
addition of boilers
use of masonry
use of venting systems

 To improve the efficiency of fireplaces, technologies such as A. addition of catalytic combustors and B. addition of boilers are used in so far. Addition of catalytic combustors hastens the process and makes use of inerts that cannot be used. The addition of boilers also adds to the efficiency by converting fluids to higher temperatures,

C. control over the business