Four Sundays do not always mean exactly 28 days.
The four Sundays of Advent form a sequence before Christmas. An Advent wreath with four candles can illustrate that sequence. This helps identify the season but does not replace the precise calendar rule.
If 24 December is a Sunday, it is also the fourth Sunday of Advent. Advent then began three weeks earlier. This shows why the simplified exam wording should not be converted into a fixed duration of 28 days.
The other three answers
The other terms name different occasions.
Day of Repentance and Prayer.
The Day of Repentance and Prayer is a single Protestant day of reflection and repentance. It does not name the whole season before Christmas.
Harvest Festival.
Harvest Festival concerns giving thanks for the harvest. It is a different occasion from preparing for Christmas.
All Saints' Day.
All Saints’ Day is observed in the Catholic Church on 1 November. Its name does not refer to the several-week Advent season.
Advent calendars and the Advent season are counted differently.
A familiar Advent calendar has doors for 1–24 December. This does not automatically make 1 December the start of Advent in the church calendar. That is determined by the fourth Sunday before Christmas.
Customs involving candles or calendars are used in different ways. To answer the exam question, you need to know the term, but you need neither an Advent wreath nor a religious celebration of Christmas.
Advent · Four Sundays · Evangelical Church in Germany ↗Four Sundays of Advent lead to Christmas.
The right term is Advent season; four weeks is the question’s simplified wording.
Three words for this question
- die AdventszeitAdvent season
- The period of preparation for Christmas in the Christian calendar.
- der AdventskranzAdvent wreath
- A wreath, often with four candles for the four Sundays of Advent.
- der Wochentagday of the week
- One of the seven days from Monday to Sunday.