TU remains same always irrespective of change in MU . defend or refute.

False, the above statement holds true only at one instance, wherein, the TU has reached its maximum point. For an instance, if the consumer goes on to increase the consumption of good beyond the point his/her TU has reached the maximum point, the MU will continue to fall, but the TU remains the same. Except this instance, in all other instances, a change in MU always bring a corresponding change in MU.

Hence, the above statement is false.