Let us consider the optimal Huffman code tree T$1$ in the figure below. T$1$ has been constructed from file Fl containir

spaces, newlines, commas, and digits

Select one or more:

a$.$ A Greedy aigorthm cannot be used to construct $71$ from F$1.$

b$.$ T$1\text{'}$s constructed using a Greedy algonithm, and the criteria adopted is the frequency of occurrence of the characters in

F$1.$

$*$ c$.$ According to T$1,$ all the characters $($colons$,$ spaces, newlines, commas, and digits$)$ occur in F$1$ with the same frequency.

d$.$ According to T$1,$ comma $*,9$ is the most frequent character

According to T$1,$ characters $"4"$ and $"5"$ are codded using the