Linnaeus’s original system had only two kingdoms, which one of the following was one of the original two?

Linnaeus’s original system had only two kingdoms. Later, this system was modified, which include 5 kingdom classifications.  

Initially in the Linnaeus’s classification, all the organisms were divided into two kingdoms. These two kingdoms were animalia and plantae.  

Later, the modifications occurred and 5 kingdom classification including animals, plants, fungi, protists and monera was introduced. The 5 kingdom classification is the most accepted classification till now.  

the answer is c) an oak tree