Which one among the following is present in the nettle leaf hairs...

Methanoic acid is the irritant present in nettle leaf hairs responsible for causing a burning sensation upon contact with the skin. When these tiny hairs pierce the skin, they release formic acid, which acts as a mild toxin. This acid stimulates pain receptors, triggering a stinging or burning sensation that can last for varying durations depending on the individual's sensitivity and the extent of contact.