Final answer:
The correct option is 1) Task.
A task is an atomic unit of work that is either entirely completed or not executed at all. Scientifically, work is the transfer of energy through force acting over a distance, which does not always align with everyday perceptions of effort, such as carrying a load on level ground without displacement.
Step-by-step explanation:
A task is an atomic unit of work that is either completed in its entirety or not done at all. In physics, work has a very specific definition which differs from everyday usage. Work is defined as the transfer of energy by a force acting on an object as it is displaced. The formula for work is W = Fd cos θ, where W is work, F is the force applied, D is the displacement of the object, and θ is the angle between the force and the direction of displacement.
An example of what people might commonly refer to as work, but which does not fit the scientific definition, is carrying a heavy load on level ground. While it may require a lot of effort, scientifically, no work is done if there is no displacement in the direction of the force. Similarly, writing an exam is considered hard work in everyday language, but it does not involve the transfer of energy through displacement, and thus doesn't fit the scientific definition of work.