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                 Which of the following pairs regarding the effect of alloying elements in steel are correctly matched?

1. Molybdenum: Forms abrasion resisting particles.

2. Phosphorus: Improves machinability in free cutting steels.

3. Cobalt: Contributes to red hardness by hardening ferrite.

4. Silicon: Reduces oxidation resistance.

Select the correct answer using the codes given below:

A) 2, 3 and 4                     

B) 1, 3 and 4  

C) 1, 2 and 4                     

D) 1, 2 and 3