fourth period
The third period is similar to the second, except the 3s and 3p sublevels are being filled. Because the 3d sublevel does not fill until after the 4s sublevel, the fourth period contains 18 elements, due to the 10 additional electrons that can be accommodated by the 3d orbitals.
The apparent effects of the gravity of unseen matter on visible objects
Volume. Gases and liquids are typically measured in milliliters (mL) or cubic centimeters (cm^3) - both of which are equivalent (1 mL = 1 cm^3).
Only C is correct.
A will produce either an methylbromide + alcohol
B will produce alcohol and alkyl bromide as well
C cyclic ether when reacted with HBr will only produce 1 product which has alcohol group (-OH group) on one end and Bromide group on the other end