Answer: Animalia
The fungi are most closely related to kingdom animalia. Previosly it was thought that fungi are close to plants as they grow in soil and are non motile.Although the animals and fungi also possess some differences between them but the phylogenetic and DNA similarities analysis put fungi more closely related to animals than to plants. The first basic similarity they share is they both are consumers and cannot produce their own food like plants. They both consists chitin.(refer cladogram of plant, animal and fungi).