Check each option for correct spelling:
Step 1: Option A - Separrate
The correct spelling is "Separate.''
Option A has an extra 'r', so it is spelled incorrectly.
Step 2: Option B - Sufficient
Correctly spelled. Means adequate or enough.
Step 3: Option C - Deceive
Correctly spelled. Means to mislead or trick.
Step 4: Option D - Ambiguous
Correctly spelled. Means unclear or having multiple meanings.
Thus, Option A is the incorrect spelling.