💡 Detailed Explanation
'～もさることながら' means 'A is certainly true, but B is also...', used to acknowledge one point (A) and then emphasize another (B). It's often used for listing positive attributes. '～はおろか' means 'let alone...' and is used in negative sentences. '～にとどまらず' means 'not limited to...' and refers to the scope or range of something expanding. '～かたわら' means 'while doing A (as a main job), also doing B'. In this sentence, we are acknowledging the lightness and adding another great quality, durability, making 'もさることながら' the best fit.