Which of the following patients is the most likely to develop S. pneumoniae pneumonia?

The patient who is 64 years old with type 2 diabetes is the most likely to develop S. pneumoniae pneumonia due to several factors associated with diabetes. Individuals with diabetes have a compromised immune system, which makes them more susceptible to infections, including pneumonia caused by Streptococcus pneumoniae. The presence of diabetes can impair the body's ability to fight off bacterial infections, leading to an increased risk of developing respiratory diseases.

While age also plays a role in susceptibility to pneumonia, especially in individuals over 65, the underlying health condition in this case—type 2 diabetes—significantly heightens the risk. The combination of age and diabetes effectively positions this patient as more vulnerable to infections overall, specifically to pneumonia caused by S. pneumoniae.

The other patients listed do have risk factors for pneumonia, such as smoking and hypertension, but they do not have the same level of immunocompromise associated with diabetes. Therefore, the 64-year-old man with type 2 diabetes represents the highest likelihood of developing this particular type of pneumonia compared to the other options.