Final answer:
The 5' capping of pre-mRNA is crucial for initiating translation, as it protects the mRNA from degradation and guides the ribosomes to start protein synthesis. OPTION (A)
Step-by-step explanation:
The pre-mRNA processing step that is important for initiating translation is capping. This step involves the addition of a 7-methylguanosine cap to the 5' end of the growing transcript. The 5' cap protects the pre-mRNA from degradation and is recognized by factors involved in protein synthesis, which help initiate translation by ribosomes.