Task: Question Answering
Input (English): Question: What is the most important prognostic factor in Stage 1 Melanoma? 
 Options:  <1> Serum LDH level. <2> Tumor thickness measured in the Breslow index. <3> The presence of clinical or histological ulceration. <4> Number of metastases. <5> The mitotic index. The mitotic index.
Output (English): 2