Answer:
first option is the correct answer i.e The amplitude remains the same, and the angular frequency increases.
Explanation:
from angular frequency, w = root(k/m)
from the question, it indicates that at some point, the blocks must have been in stationary position, as such their maximum position is at stationary. when one of the blocks is lifted, kinetic energy at that instant is negligible as such amplitude will remains the same.
And from the formular w = root(k/m), as the mass increases, angular frequency decreases and vice versa as the relationship between them is directly proportional. hence the amplitude remains the same and the frequency increases.