Answer:
a. reliability
Step-by-step explanation:
When a test administered to the same subject gives the same result after repeatedly taking the test irrespective of the time interval between them, then the test is said to be reliable.
The Intelligent Quotient test gives a score according to the person's performance. The test also takes into account the mental age of the person.
Here, the IQ test gives the same result when the same person takes the test. Hence, the test has high reliability.