BHP Group Limited and CSL Limited are both listed on ASX. BHP Group Limited pays a $100$ percent franked dividend, while CSL Limited pays only a $10$ percent partly franked dividend. What are franked dividends, and what contributes to the difference in the distribution of franked dividends between these two companies? Assume that both companies pay the same amount of cash dividends, which company's shareholders will receive a greater after$-$tax return? Provide an explanation.