Final answer:
The correct answer is d) all. Sqoop, SstableLoader, and COPY command can all be used to load data in batch.
Step-by-step explanation:
The correct answer is d) all. All of the options mentioned can be used for loading data in batch.
Sqoop is a tool designed for moving data between Apache Hadoop and relational databases.
SstableLoader is a command-line tool used to bulk load data into Apache Cassandra. It is commonly used for initial data loading or restoring from a backup.
COPY command is a feature provided by databases like PostgreSQL that allows you to copy data from a file into a table in bulk.
Therefore, all of these options are used for loading data in batch.