Identify the correct unit for rain accumulation (?) in Figure 4a.
Figure 4a: Weather data recorded during a tropical storm event
| Day | Temperature (°C) | Rain accumulation (?) | Max wind speed (km/h) |
|---|---|---|---|
| Day 1 | 29 | 15 | 45 |
| Day 2 | 28 | 42 | 65 |
| Day 3 | 28 | 120 | 110 |
| Day 4 | 27 | 180 | 145 |
| Day 5 | 26 | 95 | 90 |
mb\text{mb}mb
mm\text{mm}mm
km\text{km}km
m3/s\text{m}^3/\text{s}m3/s