b$)$ The slope distance $($SD$)$ and vertical angle $()$ between points A and $B$ were measured and their results are as shown in Figure $1.$

Figure $1$

i$)$ Compute the horizontal distance $($HD$)$ between points A and B and its standard deviation.

$(5$ marks$)$

ii$)$ If the computed standard deviation in the horizontal distance $($HD$)$ is considered too large, evaluate whether the slope distance or the vertical angle needs to be measured precisely.

$(3$ marks$)$