Answer:
Kingdom
Step-by-step explanation:
Out of all the taxonomic categories, the Kingdom is the least specific, which means it has the least filters.
I like to think of taxonomic categories as filters/sieves. If you put your animals through the Kingdom filter, then all the animals are in that category. if you have a finer sieve, then less animals get through, this goes down all the way to the most specific which is Species.
Hope this helps!