A. Escalating
I do not have the passage, however, intensify often means for a feeling to become stronger or greater—more intense.
A. Escalating is the best choice. To escalate is to become/cause something (such as a situation etc) to become more intense, often very quickly. This word is closest in meaning and use with “intensifying.”
Assessing the wrong answers:
C. Would be incorrect as dwindling means to die down, often used to describe something slowly becoming lesser either in size, strength, or intensity.
B. Would be incorrect as decreasing can’t replace intensifying without changing the whole meaning of the sentence. Decreasing means to lose something, often in value, size, or intensity.
D. Annoying is a word used to describe something that causes irritation to someone. This would not make sense as it is not similar to the word intensify.