Preheat oven to 350 degrees.
Combine flour, sugar, salt, and baking powder.
Place vegetable oil into a 1-cup measuring cup; add the egg and enough milk to fill the cup. Mix the liquid with the flour mixture.
Fold in the fruit.
Fill greased muffin cups right to the top.
To make the crumb topping, use a fork to mix together the sugar, flour, butter, and cinnamon.
Sprinkle the topping evenly over muffins before baking.
Bake for 30-35 minutes in the preheated oven, or until done.