The correct option is B bowled
This excerpt from a letter is like a feedback letter, and we need to fill in the blank numbered (2), with a verb that refers to the effect of "her communication skills and the quality of her explanations. The verb is a part of a verbal phrase, i.e, a phrase consisting of a verb and another component that work in relation to each other, the other component here is "over". From the options, 'impressed' means 'to influence the opinion of oneself to others, in a favourable way', to impress someone with your skills or something you did. It is relative to the given passage, but it does not pair up with 'over', you can't say "impressed everyone over with", you just say 'impress everyone with...', hence option A is incorrect. 'Bowled over' means 'surprise someone greatly by being impressive', it's the correct verbal phrase, it's relevant to the line that says that she did an excellent job as a guide, hence option B is correct. 'Shocked' means 'a sudden disturbance, surprise or disgust', it refers to an unpleasant surprise, and does not relate to the line. Also, 'shocked' does not form a verbal phrase with 'over'. Hence option C is incorrect. 'Bored' means 'lacking interest in an ongoing activity', it can't be used here, as it's given here "excellent work of the guide". If the guide did an excellent job, she can't possibly have bored everyone with her communication skills because it contradicts her overall impression. Also, 'bored' does not form a phrasal verb with 'over'. Hence option D is incorrect.