Average height is 6000 metres which contains some of the world's highest peaks are:

a) Himadri

b) Himad

c) Peninsular Plateau

d) Lesser Himalayas

The correct answer is option 'A' - Himadri.

The term "Himadri" refers to the Greater Himalayas, which is the highest and most continuous mountain range in the world. It is located in the northern part of the Indian subcontinent and spans across multiple countries including India, Nepal, Bhutan, Tibet (China), and Pakistan. The average height of this range is approximately 6000 meters, making it the home of some of the world's highest peaks.

Now, let's delve into the details of each option to understand why option 'A' is the correct answer:

1. Himadri (Greater Himalayas):
- The Greater Himalayas, also known as Himadri, is the highest mountain range in the world.
- It stretches over 2400 kilometers from the Nanga Parbat peak in Pakistan to Namche Barwa in Tibet.
- It includes several notable peaks, such as Mount Everest, Kanchenjunga, Makalu, and Annapurna.
- These peaks are among the tallest in the world, with Mount Everest being the highest at 8,848 meters.

2. Himad:
- There is no specific term or mountain range known as "Himad". It is not a valid option.

3. Peninsular Plateau:
- The Peninsular Plateau, also known as the Deccan Plateau, is a large plateau in southern India.
- It covers an area of approximately 1.75 million square kilometers and has an average elevation of around 600 meters.
- The Peninsular Plateau is not associated with the world's highest peaks, so it is not the correct answer.

4. Lesser Himalayas:
- The Lesser Himalayas, also known as the Middle Himalayas or Himachal, is a lower mountain range located between the Greater Himalayas and the Shivalik Range.
- It covers parts of northern India, Nepal, and Bhutan.
- The average height of the Lesser Himalayas is lower than the Greater Himalayas and does not reach the 6000-meter mark.
- Therefore, it is not the correct answer.

In conclusion, the correct answer is option 'A' - Himadri, as it represents the Greater Himalayas, which has an average height of 6000 meters and contains some of the world's highest peaks.