Let $$f:R \rightarrow (0, 1)$$ be a continuous function. Then, which of the following function(s) has (have) the value zero at some point in the interval (0, 1)?

A

$$x^9 - f(x)$$

B

$$x - \int_{0}^{\frac{\pi}{2}-x}f(t) \cos t dt$$

C

$$e^x - \int_{0}^{x}f(t) \sin t dt$$

D

$$f(x) + \int_{0}^{\frac{\pi}{2}}f(t) \sin t dt$$