Answer: directly proportional to the length that the spring is stretched.
Explanation: Deforming a spring means stretching it or compressing it, and the equation that describes this force is:
F = K*X
Where K is the spring constant, and X is the difference between the spring at rest and the actual length of the spring, so X is the distance that the spring has been stretched or compressed.
Then, the force needed to deform a spring is directly proportional to the length that the spring is stretched.