Select the most appropriate option to fill in blank number

Explanation

The sentence should be read as: “He would even try to come on walks with us.” This fits with the actual meaning of the sentence as it describes Ari trying to join the family on their walks. The other options are incorrect: (1) by suggests proximity but does not convey the idea of joining or participating, (3) at implies a specific location but does not fit the context of walking, and (4) in suggests being inside something, which is inappropriate here.