Assume a database with schema

```
TRUCK  (license-plate, maker, model, year, mileage, max-load)
DRIVER (driver-id, name, age, address, license)
TRIP   (license-plate, driver-id, date, origin, destination, miles, cargo, cost)

```

Write Relational Algebra and SQL to list the license plate of trucks that have only been used to carry fruit.

I come up with a solution where

Relational Algebra: 

[![enter image description here](https://i.stack.imgur.com/KjNM0.png)](https://i.stack.imgur.com/KjNM0.png)

SQL:

[![enter image description here](https://i.stack.imgur.com/Z2kje.png)](https://i.stack.imgur.com/Z2kje.png)

is not the correct answer. Why is that?