Put the sentences (a-c) in the correct order, then fill in the blank to make a logical text.

Vong, a small village in Ha Noi, is famous for its speciality: com (young sticky rice flakes). To make com, artisans follow a series of steps. ________
a. They wrap the final product in two layers of leaves to preserve its fragrance before selling it to consumers.
b. They preserve the techniques by passing them down to their sons. \
c. In the past, people made com by hand, but now they use machines for some steps to shorten the process.