thE pAssAgE suggEsts thAt thE Author' s hEAt-pump systEm ABsorBs hEAt From ______.
A．soil in A nEArBy FiElD
B．sun pAnEls At grounD lEvEl
C．A pipE BuriED nExt to thE wAlls
D．A tAnk oF propylEnE glyCol