Assertion. Data may be stolen through Eavesdropping.

Reason. Unauthorised monitoring of other people's communication is called Eavesdropping.

Assertion (A): Bus topology is based on a central node which acts as a hub.

Reasoning (R): Bus topology installation involves low cost.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Infrared (IR) is a wireless technology used for data communication.

Reasoning (R): Infrared involves the usage of electromagnetic radiation whose wavelength is shorter than the visible light but can penetrate easily through walls and obstacles; thus, it is used where there is an obstacle between two devices under communication.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion. A database is centrally stored data and a DBMS is a system to manage the database.

Reason. DBMS is a database management system, which is a software managing the databases.

Assertion. Data redundancy may lead to data inconsistency.

Reason. When redundant data or the multiple copies of data mismatch, it makes the data inconsistent.

Assertion. Data redundancy may lead to many problems.

Reason. In RDBMS, data redundancy is 100% removed.

Assertion. A primary key is used to uniquely identify the rows in a data table.

Reason. A primary key is a field or attribute which has a unique value for each row or tuple.

Assertion. A data table can have only one primary key.

Reason. In a data table, there can be only one attribute/field containing unique values for each row.

Assertion. There can be multiple options for choosing a primary key in a data table.

Reason. All attribute combinations inside a data table that contain unique values for each row, are the candidate keys.

Assertion. All types of keys contain unique values for each row.

Reason. A foreign-key attribute of a table is the primary key of another table.