Which of the following is the cause of expected obsolescence ?
a) change in demand b) natural calamities
c) change in tecnology d) both a and c

Dear student,

Answer should be option d. (Both A and C). 
As, machines/capital goods become obsolete due to  :
(a) change in technique of production
(b) due to change in fashion resulting in fall in demand for goods and services which the machine produces.

Regards,