Correct answer is option A. Rohit jha.km described it best. Thank you.

Some peripheral lines related to this topic:

• Selective leaching, also called dealloying, demetalification, parting and selective corrosion, is a corrosion type in some solid solution alloys, when in suitable conditions a component of the alloys is preferentially leached from the material.
• The less noble metal is removed from the alloy by a microscopic-scale galvanic corrosion mechanism.
• The most susceptible alloys are the ones containing metals with high distance between each other in the galvanic series, e.g. copper and zinc in brass.
• The elements most typically undergoing selective removal are zinc, Aluminium, iron, cobalt, chromium, and others.
• There are three steps of mechanism in dezinfication:

1. First entire brass alloy is dissolved.
2. The noble metal is re-plated (i.e. Cu in brass)
3. Active metal is leached away (i.e. Zn in brass)

• Zinc is quite reactive metal while copper is more noble metal.
• Zinc can corrode slowly in corrosive environment and leaching occurs in brass which makes porous structure of copper.
• The higher electronegative element is leached.