Which sql-mode option is required for ‘abc’ || ‘def’ to be returned as the concatenated string ‘abcdef’?

Which sql-mode option is required for ‘abc’ || ‘def’ to be returned as the concatenated string
‘abcdef’?

A.
–sql-mode=USE_CONCAT

B.
–sql-mode=PIPES_AS_CONCAT

C.
–sql-mode=NO_OR_CONCAT

D.
–sql-mode=ANSI_CONCAT