Which one of the error caused by a bias in measurementa.Parallax errorb.Random errorc.Zero errord.Systematic error

The error caused by a bias in measurements is a Systematic error.

Here's why:

a. Parallax error: This is an error that occurs when the measurement of an object's position is changed due to the change in the observer's position. It's not necessarily due to bias, but rather the angle of observation.

b. Random error: This is an error that occurs unpredictably and without a definite pattern. It's due to unknown and unpredictable changes in the experiment. It's not due to bias, but rather unpredictability and chance.

c. Zero error: This is an error that occurs when the instrument used for measurement is not set at zero before the measurement is taken. It's not due to bias, but rather an incorrect setting of the instrument.

d. Systematic error: This is an error that occurs consistently in one direction (either too high or too low). It's due to bias in the measurement system, such as a faulty instrument or a biased observer. This is the error caused by bias in measurements.