A bag of M&M$\text{'}$s has $6$ red, $5$ green, $4$ blue, and $3$ yellow M&M$\text{'}$s$.$ What is the probability of randomly picking: $($Round to $4$ decimal places$)$A bag of M&M$\text{'}$s has $6$ red, $5$ green, $4$ blue, and $3$ yellow M&M$\text{'}$s$.$ What is the probability of randomly picking:

$($Round to $4$ decimal places$)$

a$)$ a yellow?

b$)$ a blue or green?

c$)$ an orange?