it is impliED in thE lAst pArAgrAph thAt thE mEthoD usED By EArliEr EthnogrAphErs wAs ______.
A．DEtAilED notE-tAking
B．rAnDom sElECtion
C．tApE-rECorDing
D．on-thE-spot invEstigAtion