<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 64-year-old male presents to his primary care physician. Laboratory work-up and physical examination are suggestive of a diagnosis of prostatic adenocarcinoma. A tissue biopsy is obtained, which confirms the diagnosis. Which of the following is indicative of metastatic disease?? A: Decreased serum alkaline phosphatase, B: Elevated prostatic acid phosphatase PAP, C: Involvement of the periurethral zone, D: New-onset lower back pain, E: Palpation of a hard nodule on digital rectal examination,  <response>: This is a question about metastatic prostate cancer. The key is to identify which of the choices indicates that the cancer has spread beyond the prostate.Choice A about decreased alkaline phosphatase does not indicate metastatic disease, as alkaline phosphatase can be elevated in bone metastases so a decrease would not be relevant. Choice B about elevated PAP may be seen in prostate cancer but does not necessarily indicate metastases. Choice C about periurethral involvement refers to spread within the prostate, not metastatic disease. Choice D about new-onset back pain can indicate spread to the spine and is the best indicator of metastatic prostate cancer of the choices provided.Choice E refers to a nodule within the prostate, not metastatic disease.D: New-onset lower back pain 