In the polynomial f(x) = $x^5 + a\times x^3 + b\times x^4 +c\times x + d$, all coefficients a, b, c, d are integers. If 3 + $\sqrt{7}$ is a root, which of the following must be also a root?(Note that x^n denotes the x raised to the power n, or x multiplied by itself n times. Also sqrt(u) denotes the square root of u, or the number which when multiplied by itself, gives the number u)?