💡 Detailed Explanation
The correct answer is 「普及」 (fukyū), which means 'diffusion', 'spread', or 'popularization' of objects, technology, or services among the general public. 「一般」 means 'general'. 「浸透」 (shintō) means 'permeation/penetration' (often used for ideas, rules, or awareness). 「伝染」 (densen) means 'contagion/infection'.