Consider a binomial tree model in which the length of each time step is $3$ months. The annualized volatility of the underlying asset, which pays no dividends, is $0\mathrm{.}3.$ The risk$-$free rate is $10\%$ per annum $($continuously$-$compounded$).$ What is the risk neutral probability of a downward price movement $($i$.$e$.,1-$p$)$ in this model $($up to the precision of two digits after the decimal point$)?$

Group of answer choices

A: $0\mathrm{.}45$

B: $0\mathrm{.}50$

C: $0\mathrm{.}55$

D: $0\mathrm{.}60$