B. Evaporation of moisture would not produce a storm.
C. The warm and cold does not mix, instead the warm is is lifted upwards and it is this lifting that produces the surface low pressure. Also, you will need more than just instability to produce precipitation. You will also need air to rise and moisture to condense.
D. Cold air does not hold more water vapor than warm air. As a matter of fact, air can not hold moisture period. See this link for details.

http://www.ems.psu.edu/~fraser/Bad/BadClouds.html

So the answer from TJ of "C" for the first question is not correct.

Question 2, the answer is C. A wave cyclone forms between the polar air and the warm mid-latitude air. Se following link for details.
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cyc/home.rxml

A. This is not a wave cyclone. A wave cyclone does is not always associated with a squall line.
B. A storm surge is the rise in the sea level under a hurricane, not a wave cyclone.
D. Mountain lifting of air to cause rain is called orographic precipitation and may not be related to a cold front.

Edit….update: I see that TJ has now changed his answer to your first question to "A". Now his answers are correct.

2-C Wave cyclones are a group of cyclones defined as synoptic scale low pressure weather systems that occur in the middle latitudes of the Earth (outside the tropics) having neither tropical nor polar characteristics, and are connected with fronts and horizontal gradients in temperature and dew point otherwise known as "baroclinic zones".[