As stated in question the force is acting in the direction of weld means it is directed parallel to the weld or along the length of the weld. Transverse would have been correct answer if the force had act at right angle to the weld.

Explanation:
In welding, a fillet weld is a type of weld that is used to join two surfaces that are approximately at right angles to each other. It is commonly used in applications where strength and rigidity are required.

The direction of the force acting on a fillet weld can have an impact on its performance and characteristics. When the force acts in a direction parallel to the direction of the weld, the fillet weld is called a longitudinal or parallel fillet weld.

Types of Fillet Welds:
1. Transverse Fillet Weld: A transverse fillet weld is a type of fillet weld where the force acting on the weld is perpendicular or transverse to the direction of the weld. This type of weld is commonly used to resist shear forces and is typically stronger in the perpendicular direction.

2. Longitudinal Fillet Weld: A longitudinal fillet weld is a type of fillet weld where the force acting on the weld is parallel to the direction of the weld. This type of weld is commonly used to resist tensile or compressive forces and is typically stronger in the parallel direction.

3. Parallel Fillet Weld: A parallel fillet weld is a type of fillet weld where the force acting on the weld is parallel to the direction of the weld. This type of weld is similar to a longitudinal fillet weld and is commonly used to resist tensile or compressive forces.

Correct Answer:
The correct answer is option 'D' - Longitudinal or Parallel. When the force acts in a direction parallel to the direction of the weld, the fillet weld can be classified as either a longitudinal fillet weld or a parallel fillet weld, depending on the specific application and design requirements.

It is important to consider the direction of the force acting on the weld when designing and executing fillet welds to ensure that they can effectively resist the expected loads and provide the desired strength and performance.