Coins are to be put into 7 pockets so that each pocket contains at least one coin. At most 3 of the pockets are to contain the same number of coins, and no two of the remaining pockets are tO contain an equal number of coins. What is the least possible number of coins needed for the pockets ？（）

A．7

B．13

C．17

D．22

E．28

脓肾可能性大的声像表现是

A．患者高热，声像图示肾盂肾盏重度扩张成一液性区
B．患者高热，腰痛，声像图见肾脏增大，肾实质回声消失，呈多数无回声区，内见众多点状高回声，边界不清，可见与肾周围组织粘连，内可见液性区
C．患者一天前行肾穿术，声像图示肾下极脂肪囊内积聚大量液性区，肾脏浸泡其中
D．患者发热，尿频尿痛，声像图见肾脏大小正常，肾盂壁回声增强呈双层改变，肾盂积水
E．患者低热，声像图示肾脏肿大，边缘凹凸不平，肾实质厚薄不均，肾盂不规则扩张，肾盂壁上见斑片状强回声