已知函數(shù)f(x,y)在點(diǎn)(0,0)的某個(gè)領(lǐng)域內(nèi)連續(xù),且則下述四個(gè)選項(xiàng)中正確的是()。
A.點(diǎn)(0,0)不是f(x,y)的極值點(diǎn) B.點(diǎn)(0,0)是f(x,y)的極大值點(diǎn) C.點(diǎn)(0,0)是f(x,y)的極小值點(diǎn) D.根據(jù)所給條件無(wú)法判斷(0,0)是否為f(x,y)的極值點(diǎn)