Mutants of bacteriophage that carry deletions can be used to rapidly locate mutational sites of newly obtained mutants. The mapping is based on whether wild type recombinants can be recovered when the deletion mutant and the novel mutant are brought together. Four independent deletions (1 to 4) of a region were used to map 4 novel mutations (A to D). The deletions (starting from a fixed site) are shown below (the lines denote the region of deletion):

The results of mapping are summarized in the table, where '+' denotes the recovery of wild type recombinants and '-' the inability to do so.

	A	B	C	D
1	-	+	+	+
2	-	+	+	-
3	-	-	+	-
4	-	-	-	-

Further it was observed

• that out of the 4 novel mutants no revertant was observed for mutant A

• mutant B and C do not complement each other

The following conclusions were made:

A. Mutation A lies within the region of deletion 1.

B. Mutations can be ordered as A-D-B-C.

C. Mutant A could be a deletion.

D. Mutants B and C are located on 2 independent cistrons.

Which one of the following options represents a combination of all correct statements?