Answer:
I think the answer is "D"(Popular/for)
Step-by-step explanation:
All the options are in 2 forms: the 1st part being an adjective in its superlative form to the noun phrase"Disney Channel" & 2nd part being an appropriate preposition to the noun"children".
Considering the options;
A.Good/for-It's inappropriate to use b'cos of the "good" part of the option.
The question clearly stated "one of the most...",if the answer was "good", there would be no need for the phrase "the most" but directly made as "best" which is the superlative form of "good".
nb:Out of all the prepositions in the options, the best one is for.
So evaluating all options from the explanation, the best option to choose is "D"(Popular/for) as the "popular" matches well with the phrase "the most" as its superlative form & the "for" is the most app. preposition to use.