Destroy a specific Armor Stand

I need to destroy a specific armor stand but when I try the command /kill @e[type=armor_stand,c=1,r=40] it just marks the r=40 and c=1 in red. When I try to insert the coordinates of the armor stand and place a second one near it, the command block destroys both. I don’t want to destroy every single one armor stand on the map because I got lots of them here. So if anyone has an idea please tell me. By the way, I don’t have any plugins installed. Playing on 1.15.1.