Final answer:
Safety bars in the bathroom would most increase an individual's odds of survival after a heart attack by preventing falls, particularly for someone living alone with heart health concerns.
Step-by-step explanation:
After having a serious heart attack and living alone, the acquisition that would most increase your father-in-law's odds of survival would be d) safety bars in his bathroom. The safety bars would help to prevent accidental falls in the bathroom, which can be a common and dangerous occurrence, especially for individuals with a history of heart issues. On the other hand, a more reliable automobile, a dog, or a bicycle helmet may be helpful in their contexts but do not directly address the immediate safety concerns related to living alone post-heart attack like the safety bars would.