Points A,B, and C lie on a circle with centre O such that chords AB and BC are equal. If ∠AOB=(3x−15)∘ and ∠BOC=(x+45)∘, then x equals which value, and what is the measure of ∠AOC?
(a) x=30∘,∠AOC=210∘
(b) x=15∘,∠AOC=90∘
(c) x=30∘,∠AOC=150∘
(d) x=45∘,∠AOC=150∘