Tax Deduction u/s 80C - kya hota hai?

Maine read kiya hai ki sarkar ke paas 80C ke liye limit 1.5 lakh hai, lekin kya ye sabhi investment ke liye apply hota hai? Maine read kiya hai ki LIC policy, PPF account, aur ELSS fund mein investment karke 1.5 lakh tak tax-free hai, lekin kya ye sabhi investment ek saath ho sakte hain? Aur kya yeh investment ke liye sabse badi limit 1.5 lakh hai? Maine suna hai ki kuch aur investment bhi tax-free hai, jaise ki NSC, Sukanya Samriddhi account, aur ULIP policy... kya yeh sabhi investment ke liye alag-alag limits hote hain? Plz someone tose bataye!