6. Tom Ltd has control over Holland Ltd. Tom sold an equipment to Holland for $3,800,000 in January 20X5. The equipment was 3 years old when sold, and had cost Tom $4,500,000 to buy, with expected residual value $500,000. The residual value and remaining useful life of the equipment did not change. The equipment had been depreciated by Tom at 10% p.a. straight-line. The amount of the unrealised gain/loss on the sale was:

A. $500,000 gain

B. $700,000 gain

C. $200,000 loss

D. $700,000 loss

please provide calculation and explanation