A "Mason" builds a "Wall".
A "Cobbler" makes a "Shoe".
A "Farmer" grows a "Crop".
However, a "Chef" does not "Cook" a "Cook". A chef prepares food, but the relationship isn't the same as in the other pairs.
In the other pairs, the profession directly produces or works on the object (e.g., a mason works on a wall, a cobbler makes shoes). But the chef cooks food, and "Cook" isn't an object like "Wall", "Shoe", or "Crop".
Conclusion: The odd one out is (4) Chef : Cook.