Select the correct product.
(y + z)3
y3 + z3
y3 + 3y2z + 3yz2 + z3
3y + 3z
y3z3

(y + z)³

in expanded form: (y + z) (y + z) (y + z)

y(y + z) + z(y + z)    1st and 2nd set
y² + yz + yz + z²   product of 1st and 2nd set
(y² + 2yz + z²)(y + z)  multiply with 3rd set
y(y² + 2yz + z²) + z(y² + 2yz + z²)
y³ + 2y²z + yz² + y²z + 2yz² + z³
y³ + 2y²z + y²z + yz² + 2yz² + z³   Group like terms.

y³ + 3y²z + 3yz² + z³ Product of 1st, 2nd, and 3rd set ...2nd CHOICE
 

Hold on lemme do the work