The position vector of a moving particle at time t is \(r=3i+4t^2j-t^3k\) .. Its displacement during the time interval t=1 s to t=3 s is
a) \(\hat{j}-\hat{k}\)
b) \(3\hat{i}+4\hat{j}-\hat{k}\)
c) \(9\hat{i}+36\hat{j}-27\hat{k}\)
d) \(32\hat{j}-26\hat{k}\)