Concept:This question tests subject-verb agreement when the word "all" refers to everything as a single idea rather than to several people.
Explanation:The word "all" can be plural, as in "All are welcome," or singular, as in "All is well."
In the missing phrase "All ______ well," the context points to a general situation or everything, not to members of a group.
A singular subject requires a singular verb in the present tense.
The singular present-tense form is "is."
"Were" and "are" are plural forms, so they do not agree with this singular meaning.
"Will" would need a main verb after it and cannot complete the statement correctly.
Therefore, the correct completion is "All is well."
Answer:B. Is