The graph shows (government) expenditure for patients admitted to hospital in Australia, by age, for 2012–2013 - HSC - SSCE Personal Development and Physical Education - Question 19 - 2018 - Paper 1

To answer this question, we need to interpret the data represented in the graph. Observing the expenditure across different age groups, it becomes evident that expenses rise significantly in older populations. Hence, focusing on the implications of each option is crucial:

1. Mental health and injuries: While mental health is an important area, it typically does not account for the highest expenditure, especially among older age groups.

2. Mental health and respiratory diseases: Similar to the first option, while respiratory diseases can contribute to higher costs, they aren't the primary driver for substantial expenditures over $2500 million.

3. Cardiovascular diseases and injuries: Cardiovascular diseases are prevalent, especially in older populations, leading to high hospitalization costs but not necessarily over $2500 million combined with injuries.

4. Cardiovascular diseases and respiratory diseases: This option addresses conditions that heavily impact older age groups, reflecting in higher hospital expenditure, likely surpassing $2500 million due to the prevalence of these diseases in ages 65 and above.

Given the analysis of the options and data from the graph, the most accurate choice that would likely be responsible for such expenses is:

• D. Cardiovascular diseases and respiratory diseases.