Humpless cattle belong to group

Humpless cattle belong to the group Bos taurus.

Bos taurus includes European-origin cattle breeds that are characterized by the absence of a hump.

Bos indicus: Refers to zebu cattle, which are humped and are primarily found in tropical regions.

Bos bubalis: Includes domesticated water buffalo, which are unrelated to humpless cattle.

Bos arni: Refers to wild water buffalo and is also unrelated to humpless cattle.

Thus, the correct choice is Option A: Bos taurus, as humpless cattle fall under this group.