题目下列代数式中符合书写要求的是（ ）A.ab2×4ab^{2}\times 4ab2×4B.6xy2÷36xy^{2}\div 36xy2÷3C.212a2b2\frac{1}{2}a^{2}b221a2bD.14x\frac{1}{4}x41x知识点：代数式章节：未标注
