Can someone explain this glideslope question?
If you are answering an FAA Knowledge Test question, the correct answer is to level off and intercept the glide slope. 

While on the glide slope, pitch controls airspeed and power controls altitude, so you will need to add a bit of power. For small very small deviations caused by turbulence, just let the airspeed vary and use pitch for a short while. For larger deviations you won’t be able to capture the glide slope without adding power.

The amount of correction depends on how far away you are from the glide slope transmitter. Figure 139 from the Instrument Knowledge Test Supplement give you an idea of the amount of correction you need depending on how far away from the runway you are. So if you are near the outer marker, 2 dots would mean that you definitely need to add power, level off and intercept the glide slope. Near the runway 2 dots is less than 100' so a slight adjustment with pitch would be fine, presuming you were holding the glide slope until then.