Step 1: State the concept.
Methyl cellulose is a non-ionic, water-soluble cellulose derivative. Its solubility behaviour is unusual compared with most polymers.
Step 2: Recall the property of inverse solubility.
Methyl cellulose shows inverse (reverse) solubility: it hydrates and dissolves well in cold water but forms a gel and becomes insoluble when heated above its gelation temperature.
Step 3: Reason about hot water.
Option 2 (hot water) is wrong because in hot water the polymer dehydrates, agglomerates, and gels, which prevents proper dissolution.
Step 4: Eliminate soft paraffin.
Option 3 (soft paraffin) is a lipophilic, oily base. A water-soluble polymer like methyl cellulose does not dissolve in it, so it is rejected.
Step 5: Eliminate glycerin.
Option 4 (glycerin) can disperse the powder but is not the medium in which it truly dissolves best; cold water is the preferred solvent.
Step 6: Conclude.
Methyl cellulose dissolves better in cold water, which is option 1.
\[ \boxed{\text{Option 1: Cold water}} \]