The organism most similar to a tiger (Panthera tigris) from the options given is A. Panthera leo, which is the scientific name for the lion. Both tigers and lions belong to the genus Panthera, making them more closely related to each other than to the other organisms listed.
The other options are:
B. Proteles cristatus - Aardwolf, which is not closely related to tigers. C. Canis latrans - Coyote, which belongs to the genus Canis. D. Canis lupus - Gray wolf, which also belongs to the genus Canis.
So, the correct answer is A. Panthera leo.