Vitamin C

Any recommendations what vitamin C is better for my children aged 13 & 15? Yung ascorbic acid not the sodium ascorbate. Yung 13 years old ko can’t swallow capsules or tabs so I am looking for a syrup or chewable that would fit to their ages. They were recently taking ceelin chewable but hanggang sa 12 years old lang pala siya. Thanks in advance sa may ma recommend.