下列何者是應用程式廣告活動中，每個廣告群組的 HTML、圖片及影片素材資源數量上限？

In Google Ads App campaigns, each ad group allows for a maximum of 20 HTML5 assets, 20 image assets, and 20 video assets. This limit provides advertisers with sufficient variety to test different creative elements and optimize for performance without overwhelming the system. Options like 5, 8, or 10 are incorrect as they fall below the actual limit, which would restrict creative testing capabilities. The correct limit of 20 per asset type ensures flexibility for advertisers to create diverse and engaging app ads.