The correct answer is (a) Dingo.
Dingoes are unable to bark because they lack the hyoid apparatus, which is a group of bones and muscles that support the larynx and allow dogs to make the sound of barking. Without this apparatus, dingoes can only make a high-pitched whine or growl.
Alsatians, Dalmatians, and Labradors are all able to bark. Alsatians are known for their deep, booming bark, while Dalmatians are known for their high-pitched bark. Labradors have a medium-pitched bark that is often described as being friendly and welcoming.
It is important to note that there are some individual dogs of each breed that may be unable to bark due to injury or illness. However, these cases are rare.