A. Install the license key and all UTM features will be enabled for the life of the product
B. Install one license key per feature and the license key will be enabled for the life of the product.
C. Install one UTM license key, which will activate all UTM features; the license will need to be renewed when it expires.
D. Install one UTM license key per UTM feature; the licenses will need to be renewed when they expire.
参考答案：D
