Find the highest power of xxx in [((2x5+6)4+(4x6+3)3)7+((2x4+3x5)5−(x7−6)4)5]10\left[\left((2x^5+6)^4+(4x^6+3)^3\right)^7+\left((2x^4+3x^5)^5-(x^7-6)^4\right)^5\right]^{10}[((2x5+6)4+(4x6+3)3)7+((2x4+3x5)5−(x7−6)4)5]10 A120012001200B130013001300C140014001400D150015001500E160016001600