Final answer:
Option 4, 'than those of the kitchen,' is the correct punctuation and word choice, as it correctly uses 'than' for comparison and completes the thought by specifying what the dinner preparations are being compared to.
Step-by-step explanation:
The correct punctuation for the sentence 'I loved dinner preparations. No tasks seemed more magical then it.' should convey a comparison between 'dinner preparations' and other tasks. Therefore, the correct option is 4) 'than those of the kitchen.' This corrects the misuse of 'then' to 'than,' which is used for comparisons, and also completes the comparison by specifying the tasks being compared to 'those of the kitchen.'