The correct answer is: All of these.
Balti is a member of the Tibetan language family, and is closely related to Ladakhi, Parik, and Zangskari. These languages are all spoken in the Ladakh region of India, and are mutually intelligible to varying degrees.
Balti is the most widely spoken of these languages, with around 100,000 speakers. Ladakhi is spoken by around 50,000 people, Parik by around 10,000, and Zangskari by around 5,000.
These languages are all written in the Tibetan script, and share a common vocabulary and grammar. However, there are also some significant differences between them. For example, Balti has a more complex system of verb conjugation than Ladakhi, and Parik has a different set of tones than the other two languages.
Despite these differences, the four languages are all closely related, and speakers of any one of them can usually understand speakers of the others.