I am a G12 student and studied all the options in HL Maths . I guess you may be confused or find difficulty to decide your maths option. Now, I am going to give some personal suggestions.
the order in random.
There are two major parts : Number and graph theory.
This option is easier to understand. In the discrete exam, some questions can be done and get full marks. However, the proof part is a problem.
If you aim to achieve 5, it is a good idea. ( it may be difficult to achieve 7 compared with other options)
If you are strong in integration and differentiation from HL chapters.
Choose it ! ( I choose it as my option )
Statistics and Probability
Questions of it are so wordy. However, they are really doable. Enjoy playing with you calculator. ( If it is possible to choose again, I will choose it. You may feel terrible when you are learning it. After finished the whole book, it will make sense!)
Sets and groups
The same to discrete. Some questions are really easy. I normally get stunk in proof.
If you have not realized your strength yet. I think Statistics and Calculus are good options.
All the suggestions based on my own experience. Enjoy IB
Which unis have sent theirs?