# Conditionals
Decisions in code use `if`, `elif`, and `else`:
```python
if temperature > 30:
advice = "Drink water."
elif temperature > 15:
advice = "Light jacket."
else:
advice = "Bundle up."
```
The first branch whose condition is `True` runs. `elif` is short for
"else if" and there can be as many as you need. `else` is optional but
catches everything else.
## Your task
Write a function `grade(score)` that takes an integer 0–100 and returns
the matching letter grade as a string:
| Score range | Returns |
|--------------|---------|
| ≥ 90 | `"A"` |
| 80 – 89 | `"B"` |
| 70 – 79 | `"C"` |
| 60 – 69 | `"D"` |
| anything else| `"F"` |
Example:
```python
grade(95) # "A"
grade(72) # "C"
grade(40) # "F"
```