Releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
the figure shows the membrane of the thylakoid. letters from a to e indicate definite structures. letter a indicates the first protein complex of the light-dependent reactions, which is located in the thylakoid membrane. letter b indicates the multiprotein complex between two photosystems. letter c marks the second integral membrane protein complex of the light-dependent reactions. letter d marks the substance inside thylakoid. letter e indicates the flask-shaped structure, which has a canal for hydrogen ions.
a. d
b. a
c. b
d. c
e. e

A. D or electron transport chain

Explanation: first protein complex of the light-dependent reactions, which is located in the thylakoid membrane, and the electron transport chain is also a factor in it but it doesn't mention that.

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.