Vector indexing: Fill in the R code below so that each command returns just the letter $"$b$"$ from myletters. Each blank represents a single number or logical operator.

myletters $=$ c$("$a$","$b$","$c$","$d$","$e$","$f$","$g$")$

$>$ myletters$[$ type answer $]$

$>$ myletters$[$myletters type answer $"$b$"]$

$>$ myletters$[-1][$type answer$]$