Concept:
HAI refers to infections that patients acquire while receiving treatment in a healthcare facility and which were not present at the time of admission.
HAI stands for:
\[
\text{Hospital Acquired Infection}
\]
These infections are also called nosocomial infections.
Common examples include:
• Surgical site infections
• Urinary tract infections
• Ventilator-associated pneumonia
• Bloodstream infections
Step 1: Analyze option A.
Hospital Acquired Infection is the correct expansion of HAI.
Hence, option A is correct.
Step 2: Analyze option B.
Although healthcare-associated infection is a broader term used in some contexts, the standard expansion asked here is Hospital Acquired Infection.
Hence, option B is incorrect.
Step 3: Analyze option C.
“Health Acquired Infection” is not a recognized medical term.
Hence, option C is incorrect.
Step 4: Analyze option D.
“Hospital Acquired Inflammation” is not the correct expansion of HAI.
Hence, option D is incorrect.
Therefore, the correct answer is:
\[
\boxed{(A)\ \text{Hospital Acquired Infection}}
\]