What type of cipher do AES and DES belong to?

Both Advanced Encryption Standard (AES) and Data Encryption Standard (DES) are block ciphers. That means that they encrypt groups (blocks) of plain-text symbols together as a single block. If you know that either AES or DES is a block cipher, you can eliminate half of the options here. If you know that a block cipher works on groups of symbols or blocks of text, you can also eliminate half the options as incorrect.