A 4.0 kg-block attached to a 20 N/m-spring constant spring moves on a frictionless horizontal surface, back and forth between -6.0 m and +6.0 m. Which of the following will increae the period of the oscillation? Select all apply. increase the amplitude decrease the amplitude increase the spring constant of the spring decrease the spring constant of the spring increase the mass of the block decrease the mass of the block none of the above