Goldsmiths blow the outermost zone of a flame with a metallic blow-pipe for melting gold and silver. For
which one of the following reasons do they use the outermost zone of the flame?

Question

Goldsmiths blow the outermost zone of a flame with a metallic blow-pipe for melting gold and silver. For which one of the following reasons do they use the outermost zone of the flame?

Accepted Answer

(A) It is the hottest part providing most heat.

Answer

(B) This luminous zone doesn't produce any ash.

Answer

(C) It is least-hottest part protecting the design of jewelry.

Answer

(D) Middle zone vaporizes gold leading to loss of metal.