Step 1: Identify the correctly spelled word.
"Assimilated" is the correct spelling, meaning to absorb or take in.
Step 2: Check the options.
% Option
(1) ASSIMILATED: Correct spelling.
% Option
(2) ASSIIMILATED: Incorrect, extra "I".
% Option
(3) ASCIMILATED: Incorrect, misspelled.
% Option
(4) ASCEIMILATED: Incorrect, misspelled.