**Given Information:**
- Cost of the asset originally = Rs. 10 lakh
- Life of the asset = 10 years
- Scrap value of the asset = Rs. 1 lakh
- Depreciation method used = Straight line depreciation

**Calculation:**
1. To calculate the annual depreciation, we need to subtract the scrap value from the original cost and divide it by the life of the asset.
Annual Depreciation = (Original Cost - Scrap Value) / Life of the asset
Annual Depreciation = (10 lakh - 1 lakh) / 10 years
Annual Depreciation = 9 lakh / 10 years
Annual Depreciation = 90,000

2. After 6 years, the book value can be calculated by subtracting the accumulated depreciation from the original cost.
Accumulated Depreciation = Annual Depreciation * Number of years
Accumulated Depreciation = 90,000 * 6 years
Accumulated Depreciation = 5,40,000

Book Value = Original Cost - Accumulated Depreciation
Book Value = 10 lakh - 5,40,000
Book Value = 4,60,000

**Answer:**
The book value of the asset after 6 years is Rs. 4,60,000.

**Explanation:**
The book value of an asset is the value remaining after subtracting the accumulated depreciation from the original cost. In straight-line depreciation, the same amount of depreciation is charged each year over the life of the asset.

In this case, the asset originally cost Rs. 10 lakh and has a scrap value of Rs. 1 lakh. The life of the asset is 10 years. By using the formula for straight-line depreciation, the annual depreciation is calculated to be Rs. 90,000.

After 6 years, the accumulated depreciation can be calculated by multiplying the annual depreciation by the number of years, which gives Rs. 5,40,000. The book value after 6 years is then calculated by subtracting the accumulated depreciation from the original cost, resulting in Rs. 4,60,000.

Therefore, the correct option is (3) 4 lakh.