Option (iv) 'I finally realised my dream' is correct because the extract describes Arunima standing at the summit after achieving her goal. The phrase 'overwhelming sense of achievement' indicates completion of her long-cherished dream. Options (ii) and (iii) suggest future actions, which don't match the context of already reaching the summit. Option (i) expresses confidence but doesn't capture the sense of accomplishment as effectively as option (iv).