The antonym of Obscene is - 

• Option A: ‘Decent’ refers to something or someone with a satisfactory quality or facility. This is the correct option.
• Option B: ‘Objectionable’ refers to  something which is offensive or unpleasant. This is also not an antonym of the given word.
• Option C: ‘Condemnable’ refers to the act or expression of strong disapproval. 
• Option D: ‘Jealousy’ is an emotion in which one feels envious of someone or something, so it also not an answer.

Hence, option A is the correct answer.