**The Biggest Land Dinosaur: Brachiosaurus**

The biggest land dinosaur among the given options is the Brachiosaurus. Let's explore why it is considered the largest land dinosaur:

**1. Size and Weight:**
- Brachiosaurus is estimated to have been one of the largest dinosaurs that ever existed.
- It could reach lengths of up to 85 feet (26 meters) and stood about 40-50 feet (12-15 meters) tall.
- It weighed around 30-40 metric tons, making it one of the heaviest dinosaurs.

**2. Anatomy and Features:**
- Brachiosaurus had a long neck that allowed it to reach vegetation at tall heights, which suggests it was a herbivore.
- Its forelimbs were longer than its hind limbs, making its back slope down from front to back.
- It possessed a unique body structure, with a small head, a large body, and a long tail.
- Its front legs were longer than its hind legs, giving it an overall elongated appearance.

**3. Habitat and Fossil Records:**
- Fossils of Brachiosaurus have been found in North America, specifically in Colorado, Utah, and Wyoming.
- These fossils date back to the Late Jurassic period, around 154-153 million years ago.
- The discovery of exceptionally large fossils and their analysis by paleontologists led to the recognition of Brachiosaurus as one of the largest land dinosaurs.

**4. Diet and Feeding Behavior:**
- Brachiosaurus was likely an herbivorous dinosaur that fed on the leaves and branches of tall trees.
- Its long neck and high browsing ability allowed it to access vegetation that other dinosaurs couldn't reach.
- By feeding on high foliage, it may have avoided competition with other herbivorous dinosaurs.

In conclusion, among the given options, the Brachiosaurus is considered the biggest land dinosaur. Its massive size, long neck, unique body structure, and ability to reach tall vegetation make it stand out as one of the largest dinosaurs to have roamed the Earth.

Option 'c' according to ncert ...tyrannosaurs Rex is biggest land land dinosaurs...