PCA (Prometheus Certified Associate) sample exam question with answer 46

Question:
Which of the below tools answers the following question?
What was my application’s availability last month?

1. Error Budget
2. SLO
3. SLA
4. SLI

Answer:
D - SLI is the correct answer.
A - an error budget details the amount of downtime (or percentage of failing requests) that is allowable without breaching an SLO or SLA.
B - SLO is a goal/objective for an aspect of a service (availability in this case). Nothing in the given description implies a goal.
C - SLA is an agreement between parties about the level of service that will be provided and conditions that apply if the level of service is not met. Nothing in the given description implies an agreement