参考答案

正确答案：C
解析：文中提到：“Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop．”在白天当新鲜的材料暴露出来时，两次传递冰土样品的尝试由于样品在铲子里变粘都失败了。所以正确答案为C。