Indicate whether each of the following viruses is mostly associated with cervical cancer (C), Kaposi's sarcoma (K), liver cancer (L), or stomach cancer (S). Your answer would be a four-letter string composed of letters C, K, L, and S, e.g. CKLS.
( ) Hepatitis-B virus (HBV)
( ) Human immunodeficiency virus (HIV)
( ) Human papillomavirus (HPV)
( ) Helicobacter pylori