Question

when installing a battery which post should be connected first on a battery?
negative
depends on battery construction
positive
either - no difference

Explanation:

When installing a battery, the positive post should be connected first. This is a standard electrical safety and connection practice. Connecting the positive first helps in minimizing the risk of accidental short - circuits during the connection process. If the negative was connected first, and then there was an accidental contact with the positive terminal (e.g., from a tool), it could cause a short - circuit as the negative is already connected to the vehicle's chassis (ground in most cases).

Answer:

C. Positive