Answer:
a. positive disconfirmation
Explanation:
Positive disconfirmation -
In this case , the performance or the quality of some service or good is better , as was expected by the person previously , is referred to as positive disconfirmation .
In this case , the person receiving the goods or service get extremely happy and satisfied as he or she gets some better functions or quality .
Hence ,
Same case is observed with Nathan ,
Therefore , the correct term for the given information , from the given options is a. positive disconfirmation .