Philip Sidney’s arcadia was influenced by

The correct option is The Spanish romance of Montemayor.

Sir Philip Sidney’s Arcadia (specifically the Old Arcadia and the revised New Arcadia) is one of the most celebrated prose romances in the English language. When Sidney composed this masterpiece in the late 16th century, he drew significant inspiration from European pastoral traditions.
A primary influence on the structure, style, and thematic elements of Arcadia was the Spanish pastoral romance titled Diana, written by the Portuguese-born author Jorge de Montemayor and published around 1559. Montemayor’s work popularized the combination of prose narrative and inserted lyric poetry, a technique that Sidney adopted and refined. Therefore, Sidney’s work was directly influenced by the Spanish romance tradition represented by Montemayor.