in c++

Assuming that ensureLower has code that works, what statements are true given the following diagram. Select one or more: a. The constructor might look like: \begin{tabular}{|rl|} \hline 7 & Account (float bal, std: :string un) \{ \\ 8 & this->balance = bal; \\ 9 & this->username = ensureLower ( un ); \\ 10 & \} \end{tabular} class. c. The getUsername method in the following code returns something, which cannot be used to change the private field 'username': \begin{tabular}{|ll} \hline 20 & virtual std::string getUsername() \{ \\ 21 & return username; \\ 22 & \} \end{tabular} d. The ensureLower method must be public. e. The constructor might look like: g. The setter for username might look like: \begin{tabular}{|ll|} \hline 24 & virtual void setUsername(std::string un) \\ 25 & this->username = setUsername (un); \\ 26 & \} \end{tabular}