單項(xiàng)選擇題無(wú)脊椎動(dòng)物神經(jīng)系統(tǒng)的進(jìn)化趨勢(shì)是什么樣的？（）

A.梯形神經(jīng)一腹神經(jīng)索—鏈狀神經(jīng)
B.無(wú)神經(jīng)一腹神經(jīng)索—鏈神經(jīng)索一梯狀神經(jīng)
C.梯形神經(jīng)一神經(jīng)網(wǎng)一鏈狀神經(jīng)
D.無(wú)神經(jīng)—神經(jīng)網(wǎng)一梯形神經(jīng)—鏈狀神經(jīng)