Watering. You only double the final consonant when adding a suffix following the 1:1:1 rule: when adding a suffix that starts with a vowel (as -ing does): one syllable, one vowel and one final consonant. A one syllable word with one vowel and one final consonant double the final consonant when adding a vowel suffix. Other examples: dub- dubbing; put— putting. Water would never double the final consonant.

The correct answer is watering. Because the base word/verb is (to) water and the continuous tense is -ing which you add on the end. So watering. For example, “I’m watering the plants.” “His eyes are watering.”

the first one

Watering

вроде удвоение происходить если последний слог ещё и ударный, но в to water ударная a, не e (wAtering) ссылка: https://skyeng.ru/articles/okonchanie-ing-v-anglijskom-yazyke