How to remove a default drop-down box in Shopify coding?

I have imported an item from CJD dropshipping everything else seems correct. but it has imported an annoying drop-down that has only 1 option. so it’s pointless being there, how do you remove it within the shopfiy coding? could not find what I was looking for, also is there any anywhere I can learn this stuff for myself?

https://everythingmarket.store/products/6-level-height-adjustable-multi-grip-chin-up-bar-indoor-push-up-station-rack-fitness-training-equipment