The atomic radius of chlorine is 102 pm. Explain why the radius of Cl in the perchlorate anion is 41 pm, whereas the radius of Cl in the chloride anion is 181 pm. Compare both values to the atomic radius.

it's c (engineer's do their work with mechanical stuff not on any living being)

it is reliable if two scientists recorded it

alchemy hadn't scientific methods of study, appeal to mysticism and fantasy, the knowledge of chemistry and physics were modest at that time.

alchemy was - but as new rules were discovered it either changed into chemistry or it became "unscientific".