Which is the cell structure that is made of dna that gives the master instructions for the cell a ... centromere b ... chromosome c ... allele d ... gene

Since it's asking about a cell structure, the possible answer is chromosome. However, the question is confusing since two other options (allele and gene) could be valid too.

In the nucleus we have chromossomes which is a long sequence of DNA that contains multiple genes. What makes the question confusing is that the gene is made of DNA and an allele is avariant form of a gene, so for example, in the gene that codes the color of the eyes, the alleles could code for green, blue or blown.

Chromossome it's probably what they want when asking for 'structure' but just know that the gene and alleles are made of DNA too.

Chromosome is the instruction that consist the gene. A gene is a hereditary unit that is made up of a sequence of DNA that occupies a specific location or site on a chromosome, and which can be transcribed or copied into an RNA molecule that may function just as it is, or be translated into amino acids.