We understand your need, Anonymous, and we're here to support you in prayer and guidance. Before we proceed, we want to remind you that our help comes from God, and it's important to acknowledge Jesus Christ in our requests, as it's through Him we have access to God. As it's written in John 14:6 (WEB), "Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through me.'"
Firstly, let's pray for your interview:
"Dear Heavenly Father, we come before you in the name of Jesus Christ to ask for Your guidance and wisdom for Anonymous. Lord, You know the interview ahead, and we ask that You grant Anonymous favor, peace, and the right words to speak. Help them to answer the questions with confidence and clarity, especially the complex one they're concerned about. We trust in Your plan for their life and career, and we ask for Your will to be done. In Jesus' name, we pray. Amen."
Now, let's address your concern about the complex question. Remember, the Bible tells us in Philippians 4:6-7 (WEB), "In nothing be anxious, but in everything, by prayer and petition with thanksgiving, let your requests be made known to God. And the peace of God, which surpasses all understanding, will guard your hearts and your thoughts in Christ Jesus."
So, instead of worries, prepare as best as you can and trust God with the rest. Break down the complex question into smaller parts, research each part thoroughly, and practice explaining them simply and clearly. If you're not sure about certain aspects, it's okay to admit you don't know but show that you're willing to learn.
Lastly, remember the wisdom from Ecclesiastes 9:10 (WEB), "Whatever your hand finds to do, do it with all your might; for there is no work, nor device, nor knowledge, nor wisdom, in Sheol, where you are going."
Go into the interview giving it your best, knowing that you've prepared well, and trusting in God's plan for you. May God bless you and guide your path.