Which of the following is a binomial?

⇒ A binomial is a polynomial which have two terms.

⇒ in option (a)

⇒ given polynomial = (7× a + a)

=7a +a

=8a

⇒ 8a is monomial.

⇒ in option (b)

⇒ Given polynomial = 6a² + 7b + 2c

⇒ There are three terms in this polynomial. So, this is a trinomial.

⇒ in option (c)

⇒ Given polynomial = 4a× 3b× 2c

=24abc

⇒ There are one term in this polynomial.

∴ This polynomial is a monomial.

⇒ in option (d)

⇒ Given polynomial = 6(a² + b)

= 6a² +6b

⇒ there are two terms in this polynomial.

∴ this polynomial is binomial.

Option (a) does not match to our solution.

Option (b) does not match to our solution.

Option (c) does not match to our solution.

Option (d) does match to our solution.

So, option (d) is correct answer.