The major chemical compound found in human kidney stones is

The predominant constituent of human renal calculi is calcium oxalate. Clinical reviews and nephrology summaries report that calcium-containing stones represent the majority (around 70–80%) of kidney stones, and most of these are composed of calcium oxalate either alone or mixed with calcium phosphate or urate [1]. Patient-oriented kidney foundations and academic medical centers likewise state that calcium oxalate stones are the most common type and describe metabolic contributors such as excess urinary calcium or oxalate that promote their formation [3]. Other varieties (e.g., uric acid, struvite, cystine) occur but are less frequent, so calcium oxalate is the correct choice among the given options.

Sources

1. [1] https://www.sciencedirect.com/topics/medicine-and-dentistry/calcium-stone
2. [2] https://www.kidney.org/kidney-topics/calcium-kidney-stones
3. [3] https://www.hopkinsmedicine.org/health/conditions-and-diseases/kidney-stones