Answer:
option B
Step-by-step explanation:
[tex](a+b)^4\\\\=(a+b)^2(a+b)^2\\\\=(a^2+2ab+b^2)(a^2+2ab+b^2)\\\\=a^2(a^2+2ab+b^2)\\\\+2ab(a^2+2ab+b^2)\\\\+b^2(a^2+2ab+b^2)\\\\=a^4+2a^3b+a^2b^2\\\\+2a^3b+4a^2b^2+2ab^3\\\\+a^2b^2+2ab^3+b^4\\\\=a^4+4a^3b+6a^2b^2+4ab^3+b^4[/tex]
