Question

Passage:
In 1291, the Great Council of Venice enacted legislation requiring all glassmaking furnaces within the city core to be relocated to the neighboring island of Murano. While official decrees cited the imperative to mitigate catastrophic urban fire risks posed by high-temperature kilns operating in dense timber-built neighborhoods, economic historians emphasize a concomitant strategic motivation: centralized containment of glassmakers enabled tighter state surveillance over proprietary metallurgical and chemical formulations. Glassblowing had become Venice��s primary export industry, renowned throughout the Mediterranean for crystal-clear soda-lime glass, or cristallo, developed by master artisans using imported Levantine ash. To safeguard this monopoly, the Venetian state imposed severe restrictions on artisan mobility. Guild members were strictly prohibited from traveling outside the republic without explicit magistrate authorization, and exporting raw furnace materials or tools carried heavy financial penalties. However, archival evidence reveals that enforcement was nuanced rather than absolute. Although clandestine emigration of skilled glassblowers to Northern Europe did occur, the Venetian Senate frequently preferred diplomatic incentives and tax amnesties over punitive extraditions to entice absconding masters back to Murano. Consequently, while the state maintained formal legal mechanisms to isolate technological know-how, Murano’s economic dominance persisted primarily because the island concentrated specialized suppliers, specialized lime kilns, and collaborative workshop networks that could not be easily replicated abroad.

According to the passage, which of the following was the official reason cited by Venetian decrees for moving glass furnaces to Murano in 1291?