Reducing Agents for Ketones

In the context of organic chemistry, carbonyl compounds play a significant role in various biochemical reactions. Consider a scenario where a ketone undergoes a reduction reaction. This process typically involves the addition of a nucleophile to the carbonyl carbon, resulting in the formation of a new alcohol. However, the nature of the reducing agent can greatly influence the outcome of the reaction.

Which of the following reducing agents is most commonly used to reduce ketones to secondary alcohols?