40. 如右圖所示,已知該電晶體截止電壓VGS(off) = - 5 V, 直流閘源極電壓 VGS = - 4 V 時,ID = 0.35 mA, 則 R1/R2值為何? (A) 2(B) 3(C) 4(D) 5