What is$/$are the reason$($s$)$ for considering a NoSQL database, rather than a relational database?

Question $6$Select one or more:

a$.$

To support complex transactions to preserve consistency across difference transactions.

b$.$

To support a declarative query language for querying data and managing data integrity.

c$.$

To support high$-$performance queries over an extremely large amount of data, while update operations are rare.

d$.$

To support the insertion of data without a pre$-$defined schema.