Please answer the questions in the pics (all parts)

So don't take my word i'm not exactly a mathematical person but i would assume a. because while selling the soap every month you increase in sells so you would by 11 percent. the you would get the factor 0.89 which if i had to guess would be the monthly profit over 11 probably wrong tho

given that    bisects ∠dbc, which statement must be true? the answer is:   m∠abd = m∠abc