Which one of the following cannot be taken as a primary key?Question 4Answera.Streetb.Dept_idc.Register numberd.Id

The option that cannot be taken as a primary key is "Street".

A primary key is a unique identifier for a database record. Each table in a database has a column or two specifically for the primary key.

1. "Street" cannot be a primary key because it is not unique. Multiple people can live on the same street, so it would not uniquely identify a record.

2. "Dept_id" could be a primary key if it is unique to each department.

3. "Register number" could also be a primary key if it is unique to each student or employee.

4. "Id" is often used as a primary key because it can be unique for each record.

So, the answer is "Street".