Which of the following is known as “Adder’s tongue Fern? 
 

The term "adder's tongue fern" refers to several species of ferns in the genus Ophioglossum. These ferns are small and delicate, with a short underground stem. They have simple, linear leaves and a sporophyte, which is a spike-like spore-producing structure that gives the plant its common name. Adder's tongue ferns are found all over the world in a variety of habitats, including forests, meadows, and wetlands. Some Adder's tongue fern species are threatened or endangered due to habitat destruction and other factors.