$X$-rays are produced in an $X$-ray tube operating at a given accelerating voltage. The wavelength of the continuous $X$-rays has values from

• A
  $0$ to $\infty$
• B
  $\lambda_{\min}$ to $\infty$,where $\lambda_{\min} > 0$
• C
  $0$ to $\lambda_{\max}$,where $\lambda_{\max} < \infty$
• D
  $\lambda_{\min}$ to $\lambda_{\max}$,where $0 < \lambda_{\min} < \lambda_{\max} < \infty$