Assume \(\rm T\left( n \right)\) denotes the time complexity of merge sort algorithm which of the following statements is/are correct?

(i) \(\rm T\left( n \right) = o\left( {n\log n} \right)\)

(ii) \(\rm T\left( n \right) = O\left( {n\log n} \right)\)

(iii) \(\rm T\left( n \right) = \theta \left( {n\log n} \right)\)

(iv) \(\rm T\left( n \right) = O\left( {{n^2}} \right)\)