An action in a sentence can be represented in two ways, namely active and passive voice.
The passive voice always uses the past participle form of the main verb irrespective of any tense. Only the auxiliary verbs depend upon the sentence given in the active voice.
The correct answer is D)is owned.
The option D is correct as the given sentence is in the active voice and the simple present tense, and so, the blank should be filled by 'is + owned'(past participle form of the main verb).
Options A, B, and C are wrong as 'by' indicates that the incomplete sentence is in the passive voice and so 'owns' cannot be used because it is used in the active voice when the sentence is in the simple present tense, the previous sentence is in the simple present tense, and 'is owning' cannot be used respectively.