Hold/take/carry

B is the answer.

Whereas “take” and “carry” imply transporting one’s lunch in a bag or box, “hold” implies that it is in one’s hand as though about to eat it.
Of the three, A seems unlikely, B seems most likely, and C is less likely (since it implies keeping it ready to eat at a moment’s notice.)

How about "I still have my lunch to have it after work"? Does it sound awkward or stupid (due to repetition of 'have')? To avoid repeating the same word, should I say "I still take my lunch to have it after work"?

“I still take my lunch to have after work.” That works well. The word “it” is unnecessary, since you already have the word ‘lunch’. You could feasibly use, “I still have my lunch to have after work.” (...to eat after work" is better.)