Explanation:

The sentence describes the action of fans gathering around someone. The verb 'surround' typically takes the preposition 'by' to indicate who or what is doing the surrounding. Thus, 'surrounded by fans' is the correct and idiomatic usage. Options (1) 'encircled with', (3) 'surrounded into', and (4) 'encircled to' use incorrect prepositions or are grammatically awkward in this context. 'Encircled by' would also be correct, but 'encircled with' is not standard here.