Concept:The efficiency of labour depends on workers' ability, motivation, and working conditions, not on their race or colour.
Explanation:Education and training improve workers' skills and productivity.
Provision of welfare services, such as healthcare and housing, keeps workers healthy and motivated.
Quality of other factor inputs, like better machines and tools, raises the output per worker.
Race and colour of the workforce have no direct influence on how efficiently labour works.
Therefore, race and colour of workforce is not a factor affecting labour efficiency.
Answer:C. Race and colour of workforce