Use the expression below to answer the questions. Complete parts a through d below.

$9y+3+6x$

a$.$ How many terms are there in the algebraic expression?

b$.$ What is the numerical coefficient of the first term?

c$.$ What is the constant term?

d$.$ Does the algebraic expression contain like terms? If so$,$ what are the like terms? Select the correct choice below and, if necessary, fill in the answer box to

complete your choice.