This information appears on page 15 of the source. Which citation format is correct?

(Price et al. 15)
I am posting for others... feel free to take the points.
The estimated ARMS effect indicates a 17-percent increase in yields for herbicide-tolerant cotton adopters nationwide. In some regions, herbicide-tolerant cotton yields may have been lower than for conventional varieties. In particular, farmers in the Mississippi Portal encountered serious and unexpected problems with their herbicide-tolerant cotton during the 1997 growing season (Virginia Cooperative Extension). Some growers found deformed bolls and bolls that dropped off the plants. About 20 percent of the region’s herbicide-tolerant cotton was affected. However, the problems may have been caused by factors other than the herbicide-tolerant technology itself, such as soil type and weather conditions.

—Gregory Price, William Lin, José Falck-Zepeda, and Jorge Fernandez-Cornejo. “Size and Distribution of Market Benefits From Adopting Biotech Crops.” United States Department of Agriculture. November 2003.

assuming the underlined word is "regnant", the correct answer is b) ruling.

i decided to stay late in the laboratory to continue my experiment with the lightbulb. at midnight, thomas edison opened the door and walked in with his head held high.

1. he leaned on the wall and observed me carefully.

2. his harsh scrutiny made me self-conscious of my skills in the lab.

3. perhaps it was just me, but the air in the laboratory began to thicken as i found myself having difficulty to breathe.

4. i turned to look at him fully as i mentally prepared myself for what my very first words would be to thomas edison.

5. the next couple of seconds shocked me. it wasn't me who spoke, but rather him and with diction i could never think of using in a simple sentence.

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hey, sorry if this was bad, i really didn't know what to write but i wanted to you. is there anything that you had to include within the excerpt?

the correct answer is option d. none of these. it is noted that options a, b, and c share the same content.

despite the valid answer provided at the last sentence of each of the options, a question/answer format shouldn't include humourous themed responses such as "you bet your thermal pj's we do." - unless of course, the answer is carried out in an informal environment. this could be replaced with a simple "yes" or "it is necessary".

the question should be re-phrased to a more appropiate syntaxis. instead of "do we need the greenhouse effect? ", it should be written as "is the greenhouse effect necessary? " in order to give it a general scope, instead of limiting the answer to the needs of "we" the humans.

im going to need some more info to answer this qeustion for you