Which State in India has the largest extent in irrigation (percent)?
In simple words, which State in India has the largest means Punjab. In Irrigation and Canals, this is one of those facts you just remember once and it stays. Think of which State in India has the largest and Punjab together. Once you see the link, you will not need to think twice in the exam.
Ref: [Uttarakhand PCS (Pre) 2016] | Majid Husain, Geography of India, and NCERT Geography textbooks discuss Irrigation and Canals and explain the Indian geographical features and patterns that support the correct answer for this question.