NoSQL databases:. a) are geared toward transaction consistency; not performance.
b) support only small amounts of sparse data.
c) provide fault tolerance.
d) are based on the relational model.

Option c (provide fault tolerance) is the appropriate choice.

Explanation:

Some other options in question are not relevant to something like a particular circumstance. So that the option above will be the appropriate one.

c) provide fault tolerance.

Explanation:

Fault tolerance means the ability of a computer or network to continue working without any interruption when any of its components fail. Fault tolerant systems use backup components that takes place of the failed components so that there is no loss of service. In cases of failure the system can continue at a reduces level instead of failing completely. SQL database is not fault tolerant so it willl not function in case of interruption or system failure.