Which word best completes the sentence? the reason for our tardiness was we got stuck in traffic.

I'm not sure what your options are, but here's what I've come up with:

The reason for our tardiness was because we got stuck in traffic.

either b or c, sorry idk

a. "to practice" is the best phrase to complete the sentence.

explanation:

during the summer, she likes to practice her soccer skills so that she is ready to play in the fall.

(note that : all the other options "the practicing of", "practice for" and "to do a practice on" are inappropriate as they make the sentence grammatically incorrect.)