What is the reason for the occurrence of systematic errors in an instrument ?

What is the reason for the occurrence of systematic errors in an instrument ?
 
(a) No use for a long time
 
(b) High use
 
(c) Manufacturing fault
 
(d) Delivery fault
 
I have been asked this question in my homework.
 
I would like to ask this question from Accuracy, Precision of Instruments and Errors in Measurement topic in section Units and Measurements of Physics – Class 11
Select the correct answer from above options 
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