There are several reagents that can be used to effect addition to a double bond, including: acid and water, oxymercuration-demercuration reagents, and hydroboration-oxidation reagents. Inspect the final product and select all the reasons why oxymercuration-demercuration was chosen to effect the following transformation instead of the other reagents.

A. Oxymercuration-demercuration reagents prevent carbocation rearrangements.
B. Oxymercuration-demercuration reagents favor carbocation rearrangements.
C. Addition with acid and water as reagents avoids carbocation rearrangements.
D. Addition with acid and water as reagents allows carbocation rearrangements.
E. Hydroboration-oxidation reagents yield the anti-Markovnikov product of addition.
F. Hydroboration-oxidation reagents yield the Markovnikov product of addition.
G. The reaction requires the Markovnikov product without carbocation rearrangement.
H. The reaction requires the anti-Markovnikov product with carbocation rearrangement.

The answer to your question really depends on three things: how much water you have, how cold it is to start out, and how cold the things around it are. water actually freezes when it gets to 32 degrees fahrenheit (0 degrees celsius), but the time it takes to get there may be different.  let's start with the first. if you take two glasses, and fill one with a tiny bit of water, and the other about halfway, then put them both in the freezer, the one with less water will freeze first (you can try this at home, but i recommend using plastic cups and not glass ones).  now let's move on to the second part. let's say you have two glasses, and you fill one with really cold water that has been in the refrigerator, and the other with really hot water from the sink. if you put both of them in the freezer, the one that started out colder will freeze first.  for the third part, let's imagine that you have two glasses with the same amount of water in them, and the water is at the same temperature. imagine putting one outside on a really really cold day in georgia, and having a friend in alaska put one outside on the same day. since it would be so much colder in alaska, the glass of water there would freeze before yours.  so, if you took a tiny bit of really cold water in a glass, and put it outside on a cold day in alaska, it would freeze a lot faster than a big glass of hot water outside on a cold day in georgia. 

There are two molecules. check the attached file for the solution.