Which is the largest known tree in the plant kingdom?
A. Pinus
B. Sequoia
C. Metasequoia
D. Cedrus

Hint: Sequoia sempervirens found on the pacific coast in North America is taller about 115.5 m of height. Pinus also includes shrubs. Metasequoia found in the northern hemisphere will not grow more than 50 m. cedrus have thick ridged bark and broad levels of branches. It cannot grow much higher than 40 m.

Complete answer:
Plant kingdom includes a wide variety of the plants. Sequoia sempervirens that include the world's largest trees is the species of the genus Sequoia in the cypress family Cupressaceae. The common names of these species are: coast redwood, coastal redwood and California redwood. These are evergreen plants, long-lived trees. The tallest trees on the earth included these species. The height of this type of tree can be 379 feet (115.5m). These trees are included among the oldest living things on the earth.
Metasequoia includes the fast growing deciduous trees. Conifers are known as redwoods. The living of this group is native to Lichuan County in Hubei, china. It can grow up to 165 feet (50 m).
Pinus are classified in the genus of approximately extant tree and shrub species. Pinus is commonly called pines. Pines are of two types: hard pines and soft pines.
Cedrus includes in the genus of coniferous trees in the plant family. They can grow up to 30-40m (occasionally 60 m) tall.
From the above information we can say that Sequoia is the largest tree in the plant kingdom.

So, the correct answer is option B.

Note: The tallest tree of the world is in California named Hyperion. It includes most of the sequoia. Fungus individuals include the world’s largest living organisms. They can extend for 965 hectares. Their approx age is 2,400 to 8,600. The largest vegetable structure is designed to host an art collection. The thickest tree is found in Mexico called Arbol Del Tule.