Which risk escalates drastically for miners creating tunnels beneath city walls during a siege?

💡 Explanation

Counter-mining presents a critical threat because undermining causes structural Collapse, potentially trapping their own forces rather than successfully breaching defenses; therefore, defenders collapsing the invading tunnel is the correct answer, rather than simple accidental collapse alone.

• Which risk to accurate navigation sharply increased when a knotted rope's density changed on a Viking longship?
• Which consequence arose during early ironclad ship construction because of armor plating limitations?
• Which outcome results when improperly heat-treating crucible steel during the 18th century?
• Which navigational risk increased for 18th-century square-rigged ships traversing the Strait of Magellan?
• Which systematic error affects celestial navigation using a sextant during a long voyage when temperature varies considerably?
• Which trade outcome occurred when the Byzantine Empire used silk cloth as tribute payment?