(c) Explain the application of the ‘two thirds rule’ in relation to a composite supply of goods and services, indicating how a trader may seek to minimise its effects. (5 marks)

下颌下淋巴结群首先流向的淋巴结是（）

A.颈深淋巴结下群

B.颈深淋巴结上群

C.颈淋巴干或胸导管

D.颈前淋巴结群

E.颈浅淋巴结群