The question appears to be about the effects of restrictions on the contraction of solidifying metal. Correct Option: - **Cold shut** **Explanation:** When a solidifying metal is restricted from shrinking freely, it often results in defects such as cold shuts, which are weld lines or incomplete fusion caused by the metal not flowing properly due to constraints. Other options: - **Defective surface**: Usually caused by contamination or improper surface preparation. - **Swell**: Generally related to expansion, not contraction. - **Cracking and tearing**: Can occur but are not specifically caused by restrictions on shrinkage like cold shuts. **Therefore, the correct answer is: Cold shut.**