Long) and 1 public F: foundation code. A customer wants to buy two kilograms of candy. The salesperson places a 1-kilogram weight on the left pan and puts the candy on the right pan to balance it, then gives the candy to the customer. Then, the salesperson places the 1-kilogram weight on the right pan and puts more candy on the left pan to balance it, and gives this to the customer as well. The two kilograms of candy given to the customer ().
(A) is fair
(B) the customer gains
(C) the store loses
(D) if the long arm is more than twice the length of the short arm, the store loses; if less than twice, the customer gains
4. C (Hint: Set up the city

Bi Chang: Left Bi Chang $=a: b$, then the weight of the sugar fruit in the first weighing is $\frac{b}{a}$ kilograms; the weight of the fruit in the second weighing is $\frac{a}{b}$ kilograms. Since $a \neq b$, so $\frac{b}{a}+$ $\left.\frac{a}{b}=\frac{(a-b)^{2}}{a b}+2.\right)$