The length of the badminton court for singles is:

The correct answer is 13.40 m.

Let's understand the standard dimensions of a badminton court as defined by the Badminton World Federation (BWF) — the global governing body for the sport.

Step 1: Know the two types of badminton courts
A standard badminton court is used for both singles and doubles play, but the width differs between the two formats. The length, however, also has a specific standard value used for singles play.

Step 2: Official BWF Court Dimensions
According to official BWF regulations:

- Full court length (doubles): 13.40 m
- Court width for doubles: 6.10 m
- Court width for singles: 5.18 m
- Length for singles play: 13.40 m

Step 3: Clarify the length for singles
The length of the badminton court remains 13.40 m for singles. Unlike the width (which is reduced for singles play by excluding the outer tramlines), the length of the court does not change — it stays at 13.40 m from baseline to baseline. The back tramlines are included in singles play, maintaining the full 13.40 m length.

Step 4: Eliminate the incorrect options

- 13.44 m — Incorrect; this is not a standard BWF measurement.
- 13.55 m — Incorrect; no such dimension exists in BWF rules.
- 14 m — Incorrect; this exceeds the official court length.
- 13.40 m — ✅ Correct; this is the official BWF-mandated length.

Conclusion:
As per the Badminton World Federation (BWF) official rules and regulations, the length of the badminton court for singles is:

\text{Court Length}=13.40\text{m}

Therefore, the correct answer is 13.40 m.