In the following passage some of the words have been deleted. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.

Comprehension:
The difference between the solar radiation absorbed and the thermal radiation emitted to space (1) _____ radiation budget of the earth. Since there is no appreciable long-term trend in planetary temperature, it may be (2) ______ that this budget is essentially zero on a global long term average.

The rate of temperature change in any region is directly (3) ______ to energy budget of the region and inversely proportional to its heat capacity. While the radiation (4) ______ may dominate the average energy budget of many surfaces, nonradiative energy transfer and storage also are (5) ______ important when local changes are considered.

Select the most appropriate option to fill in blank number 1.