It runs through...
Russia
Romania
Poland
A spit could form from a rocky headland where prevailing winds would blow at an angle to the rocky headland, gradually depositing sand and shingle at that place.
A spit is a permanent landform resulting from marine deposition and wind deposition. It is usually a long and narrow accumulation of sand or shingle with one joined to the land and the other end projecting at a narrow angle out into the sea.
Salt marshes sometimes form on the sheltered side of a spit.
The English Channel is the body of water between England (Great Britain) and France, it is connected to the Atlantic Ocean.
Being a body of water, it can't be a water way - so the answer b) is false.
In fact, from the description above you know that the answer a. an extension of the Atlantic Ocean between England and France is true.
The hubble telescope thing