Negative tropism is described as
1. growth towards a stimulus
2. growth away from stimulus
3. growth is not affected by stimulus
4. growth is not affected by internal forces

2. growth away from stimulus

Tropism is a descriptive reaction of a certain stimuli on how an organism responds to the confronted stimuli which can be called positive tropism or negative tropism.
In positive tropism as the proposed answer toward  involves the organism leaning forward or direct to the acting stimuli whereas the negative tropism is exactly the opposite. 

The salt in the sea water dehydrated the sailor because her body could not take in the amount to salt in the sea water