Which type of cancer is found in lymph nodes and spleen?

Which of the following statements are correct?
$A.$ Computed tomography and magnetic resonance imaging detect cancers of internal organs.
$B.$ Chemotherapeutic drugs are used to kill non-cancerous cells.
$C.$ $\alpha$-interferon activates the cancer patients' immune system and helps in destroying the tumour.
$D.$ Chemotherapeutic drugs are biological response modifiers.
$E.$ In the case of leukaemia,blood cell counts are decreased.
Choose the correct answer from the options given below:

Assertion $:-$ Metastasis is the most feared property of malignant tumors.
Reason $:-$ Cells sloughed from such tumors reach distant sites through blood and interfere in functions of other tissue.

Study the following sentences.
$I.$ The cells of malignant tumours divide erratically.
$II.$ They are malignant tumours of epithelial cells.
$III.$ They are malignant tumours of organs that originate from mesoderm.
$IV.$ These tumours are found in organs such as spleen and lymph nodes.
Which of the above are true for angiosarcoma?

The process of spreading cancerous cells to distant sites is known as

Cobalt therapy and iodine therapy used in the treatment of cancer are included in which of the following?