A
分析:如果4a=b,(a、b均不為0),則b÷a=4,即b是a的整數(shù)倍,求兩個數(shù)為倍數(shù)關系時的最大公因數(shù)和最小公倍數(shù):兩個數(shù)為倍數(shù)關系,最大公因數(shù)為較小的數(shù),最小公倍數(shù)是較大的數(shù);由此解答問題即可.
解答:由題意得,b÷a=4,可知b是a的倍數(shù),所以a和b的最大公因數(shù)是a;
故選:A.
點評:此題主要考查求兩個數(shù)為倍數(shù)關系時的最大公因數(shù)和最小公倍數(shù):兩個數(shù)為倍數(shù)關系,最大公因數(shù)為較小的數(shù),最小公倍數(shù)是較大的數(shù).