CORRECT answer is "about whether we should move".In the given sentence, the use of the conjunction 'if' is incorrect.The conjunction 'if' is used to INTRODUCE a condition (something that must be SATISFIED before something else occurs).The conjunction 'whether' is used for expressing a doubt or choice between alternatives.Therefore, the conjunction 'whether' should be used in place of the conjunction 'if'.Also, the form of the verb 'shall' is incorrect in the underlined SEGMENT as the given sentence is in the past TENSE.Therefore, the past tense form of the verb 'should' be used in place of the base form of the verb 'shall'. Thus the correct sentence is: There was an argument about whether we should move to another city.