I believe your answer should be A (4x+3) because if im not mistaken you have to factor out 64x^2+96x+36 which will lead you to 4(16x^2+24x+9)/16x+12 then you factor 16x+12 which gives you 4(16x^2+24x+9)/4x+3 now and for your final factor you factor 16x^2+24+9 now which gives you (4x+3)^2 and for your final step you cancel the common factor which will give you (4x+3)