Based on the premise "Because a large proportion of street costs are fixed,27 the unit (per piece) street cost initially declines rapidly as volume increases and continues to decline at a decreasing rate.", can we conclude the hypothesis "By concurrently building more units at one time, costs can be lowered." is true (see options)?

Select from the following.
-- yes.
-- it is not possible to tell.
-- no.
it is not possible to tell