ANS:B - clarifier

Traces of solids are most effectively removed from a liquid using a sparkler filter. Here's a brief explanation of each option:

1. Classifier:
   • Used for sorting particles by size or density, but not typically for removing fine traces of solids from liquids.
2. Clarifier:
   • Used to remove suspended solids from liquids through sedimentation, but it is more suitable for removing larger particles rather than fine traces of solids.
3. Sparkler Filter:
   • A type of pressure filter that is highly effective for polishing filtration, removing very fine particles, and traces of solids from liquids. It uses filter plates and media to achieve fine filtration.
4. Rotary Vacuum Filter:
   • Used for continuous separation of solids from liquids, but it is generally employed for slurries with higher solid content and not as effective for removing trace amounts of fine solids.