In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Presta valves are the skinnier of the _ valve types.
[EX A]: two

[EX Q]: Architectural shingles are twice or _ times as thick as ordinary shingles.
[EX A]: three

[EX Q]: Tomatoes do require at least four to _ hours of sunlight.
[EX A]:
six