ANS:A - braze

Filler metal is used in braze welding. Explanation:

• In braze welding, also known as brazing, a filler metal with a lower melting point than the base metals being joined is used to bond the materials together.
• The filler metal is melted and flows into the joint, forming a strong bond between the base metals upon solidification.
• Braze welding is commonly used for joining dissimilar metals or metals with different melting points, as well as for applications where the base metals are thin or heat-sensitive.
• It is often used in plumbing, automotive, and jewelry manufacturing industries, among others.