phase
length
spell
time
Answer is Right!
Answer is Wrong!
The correct answer is C. spell.
A spell is a period of time during which something happens or exists. In this case, the warm weather happened for a period of time in February.
The other options are not as accurate. A phase is a stage in a process or development. A length is a measurement of distance or duration. A time is a point or period of indefinite duration.