Final answer:
To calculate the duration of a presidency from a given starting year, subtract the starting year from the current year. Assuming the current year as 2023, the president who started in 2020 has been in office for 3 years, which corresponds to option A.
Step-by-step explanation:
The question When did the president start? How long has he been president? involves calculating the duration of a presidential term from a given start year. Without a specific context of which president or country is being referred to, we can assume this is a hypothetical situation meant to test understanding of simple subtraction to calculate the length of time from a certain year until the present.
To solve this, we would subtract the starting year from the current year. If we assume the current year is 2023 for this question:
- A) 2023 - 2020 = 3 years.
- B) 2023 - 2015 = 8 years, not 10 years.
- C) 2023 - 2019 = 4 years.
- D) 2023 - 2010 = 13 years.
Given these calculations, option A fits the current year 2023, suggesting the president started in 2020 and has been in office for 3 years.