Which of the following is equivalent to gcd(a,b)×lcm(a,b)\gcd(a, b) \times \text{lcm}(a, b)gcd(a,b)×lcm(a,b) for positive integers aaa and bbb?
a+ba + ba+b
a×ba \times ba×b
a2+b2a^2 + b^2a2+b2
a+b2\frac{a+b}{2}2a+b