Which sentence correctly links two independent clauses? (3 points)

a
The packing box had been used and reused; a heavy layer of packing tape was all that held it together.

b
The packing box had been used and reused, a heavy layer of packing tape was all that held it together.

c
The packing box had been used and reused and a heavy layer of packing tape was all that held it together.

d
The packing box had been used and reused now a heavy layer of packing tape was all that held it together.