Which of the following statements are True?

a) As the local circuity factor increases, the delivery cost also increases.

b) Establishing a hub incurs initial setup cost but later reduces transportation related costs enabling higher LOS.

c) Sub-set/Sub-assembly of a product being sold individually along with the main product comes under economies of scope.

d) In many to many cases, the focus is on aggregating high volume lanes.

e) Direct moves are profitable when there are strong economies of density.

*I know a, b, and e are true. My answer is showing up as only partially correct. Of the remaining choices, c and d, which is also true?