Determine the correctness or otherwise of the following Assertion(a) and Reason(r):
Assertion (a): Deoxidation and decarburisation of liquid steel are done by vacuum treatment process.
Reason (r): Decreased partial pressure of CO(g) promotes deoxidation and decarburisation.

A. The temperature of L.D. furnace is maintained at around 1600°C B. The basicity of slag is maintained at around unity C. Dephosphorisation and decarburisation should proceed simultaneously D. High silicon hot metal may lead to sloping

A. CaO, because Ca²⁺ ions are oxidising to the elements B. CaO, because O^2- ions are oxidising to the elements C. FeO, because Fe²⁺ ions are oxidising to the elements D. FeO, because O^2- ions are oxidising to the elements

A. Plain carbon steel B. Clean steel C. Alloy steel D. None of these

A. a is false but r is true B. a is true but r is false C. a is true and r is also true, but r is not the reason for a D. a is true and r is also true, and r is the reason for a