Task: Instance Description Understanding (ontology: Sciences/Computer_Science)

Which of the following definitions best describes the instance 'pM1a (colon)'?

A. A pathologic distant metastases stage for colon according to AJCC 7th edition indicating that metastasis is confined to one organ based on clinical assessment.
B. A pathologic distant metastases stage for colon according to AJCC 7th edition indicating that metastasis is confined to one organ and histologically confirmed.
C. A pathologic distant metastases stage for colon according to AJCC 7th edition indicating that there is microscopic evidence confirming distant metastatic disease.
D. A pathologic distant metastases stage for colon according to AJCC 7th edition indicating that there are no symptoms or signs of distant metastasis.

Answer: A pathologic distant metastases stage for colon according to AJCC 7th edition indicating that metastasis is confined to one organ and histologically confirmed.