You want to deploy a stateful application on GKE that requires both read and write access to a persistent disk. What is the recommended storage solution to meet this requirement?

GCE Persistent Disks with ReadWriteOnce is the correct solution because it provides durable, block storage that can be attached to a single node in ReadWriteOnce mode, which is suitable for stateful applications requiring exclusive read/write access from one pod. Cloud Storage buckets are object storage and don't offer the block-level performance or POSIX compliance typically needed for stateful applications. Cloud Filestore provides network file storage (NFS) with ReadWriteMany access, but it's generally more expensive and might be overkill if only a single pod needs access. Cloud Spanner is a relational database, not a file system for application state. Local SSDs are ephemeral and not suitable for persistent data. GCE Persistent Disks with ReadWriteMany is not a supported access mode for GCE Persistent Disks.