How do you specify environment variables in a Pod manifest?

Correct answer: Both env and envFrom fields

Option A is correct because Kubernetes supports two complementary approaches for injecting environment variables into containers: the `env` field allows you to define individual key-value pairs directly or source them from ConfigMaps and Secrets, while the `envFrom` field allows bulk import of all keys from a ConfigMap or Secret, and both fields coexist under `spec.containers`. Option B is only partially correct because it omits `envFrom`, which is also a valid and commonly used mechanism. Option C is wrong because there is no `environment` field in the Pod manifest's `metadata` section; metadata holds labels, annotations, and names, not runtime configuration. Option D is only partially correct because it omits the `env` field, which is equally valid for setting environment variables.