Final answer:
The regular 3rd person singular present tense ending in English is -s.
Step-by-step explanation:
The regular 3rd person singular present tense ending in English is 1) -s.
When a verb is in the 3rd person singular form (he, she, it), the present tense ending is typically -s. For example, 'He walks to school' or 'She eats an apple.'
Other options like -es and -ies are used with specific verb forms, such as verbs ending in -sh, -ss, -ch, or -x. For instance, 'She pushes the door' or 'He misses the bus.'
The option -ing is not the regular 3rd person singular present tense ending. It is used for forming the present participle or the present progressive tense. For example, 'He is running' or 'She is studying.'