The cognitive abilities of those taking a test is an example of non-random error.
Option: III
Step-by-step explanation:
Random error is always happened in a measurement. It is caused by fluctuations in the readings of a measurement instrument of the instrumental reading. Random errors happen during counting process. Non-random error or non -sampling error occurs in subjective thing.
Sampling represents the whole data in the form of sample. It works as a representative. Random sampling includes collection of data on the basis of randomly chosen data whereas no random data is chosen by following step wise method.