ANSWER
C. DIMINISHING Returns to property/ scale
Step-by-step explanation
Returns to Scale is a production concept used in Long Run (when all factors are variable i.e changeable)
It denotes relative change in output when all inputs change in same proportion .
Increasing Returns to Scale : Proportionate Increase in Output > Proportionate Increase in all inputs .
Constant Returns to Scale : Proportionate Increase in Output = Proportionate Increase in all Inputs .
Negative Returns to Scale : Proportionate Increase in Output < Proportionate Increase in all Inputs .
So : If all inputs are doubled (X2) - If output increases equal i.e double (X2) , Constant Returns to Scale . If output increases more i.e triple (X3) , Increasing Returns to scale . If output increases less i.e (1.5X) , Decreasing Returns to Scale.