If a dog is relaxed, alert, and confident as evidenced by its ears up or relaxed naturally and its eyes bright and alert with good contact, the dog’s tail will most likely be
a. sticking straight out behind.
b. held loosely and lowered behind its body.
c. stiff and lifted straight in the air.
d. fully tucked under its body between its legs.

The correct option is A.
When a dog is relaxed, alert and confident, it will holds its tail high or sticking straight out behind it. Dogs' tails can be used to decipher their emotions. A dog holding its tail down and tucked between its legs is signalling submission while a dog with its tail high may be signalling excitement, alertness or dominance.