Find out whether there is any grammatical error in below sentence.In management, as you rise higher, / the problems you face becomemore and more unstructured and you can't just fall back on / the tools you had been?

• A. In management, as you rise higher,
• B. the problems you face becomemore and more unstructured and you can't just fall back on
• C. the tools you had been
• D. No error