Option C is correct because it configures the preload.keys correctly for Redis L2 caching on an Adobe Commerce on-premise instance. Redis L2 caching is a feature that allows storing the cache data in both Redis and the local file system. This way, the cache data can be loaded faster from the local storage, while Redis acts as a cache invalidation service. To use Redis L2 caching, the backend option for both frontend => page_cache and frontend => default must be set to Magento\Framework\Cache\Backend\RemoteSynchronizedCache1. To enable the preload feature, which reduces the number of requests to Redis, the preload.keys option must be specified with the cache keys that are loaded on each frontend request. However, unlike Redis L1 caching, the preload.keys must include the suffix :hash to indicate that only the hash values of the cache data are stored in Redis2. Therefore, the correct configuration for preload.keys is:

[ ‘762_EAV_ENTITY_TYPES:hash’, ‘762_GLOBAL_PLUGIN_LIST:hash’, ‘762_DB_IS_UP_TO_DATE:hash’, ‘762_SYSTEM_DEFAULT:hash’, ],

Option A is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It uses the id_prefix of frontend => page_cache (063_) instead of frontend => default (762_) for the cache keys. This will cause a mismatch between the cache keys and the cache data, and result in incorrect or missing cache data. Moreover, it does not include the suffix :hash for the preload.keys, which is required for Redis L2 caching2.

Option B is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It does not include the suffix :hash for the preload.keys, which is required for Redis L2 caching2. It also uses a wrong cache key (GLOBAL_PLUGIN_LIST) instead of GLOBAL_PLUGIN_LIST.

Option D is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It uses a wrong id_prefix (162_) instead of frontend => default (762_) for the cache keys. This will cause a mismatch between the cache keys and the cache data, and result in incorrect or missing cache data. It also uses a wrong cache key (EAV_ENTITY_TYPES) instead of EAV_ENTITY_TYPES.

References:

1: Two-level caching | Adobe Commerce Developer Guide

2: Use Redis for default cache | Adobe Commerce Developer Guide