Answer:
a. sensitization
Step-by-step explanation:
Sensitization, is a term in psychology, that describes a non-associative learning process in which there is strengthening of a neurological response to a stimulus due to the response to a secondary stimulus.
An obvious example, is if a loud sound is suddenly heard by an individual, such person may startle at that sound. If a shock is given following the sound, then the next time that particular sound occurs, the individual will subsequently react even more strongly to the particular sound.
Hence, in this case, the change that has come over my normal reaction to sirens is sensitization.