Can anybody help me with this exercises?

Which sentence uses the past tense of to study correctly? a. mark is studying for his math test with margie. b. mark will study for his math test with margie. c. mark studied for his math test with margie.

Excerpt from the ultimate fighting championship mary o'dell 1 american interest in mixed martial arts is growing. both male and female athletes are invited to compete, although this sport is not recommended for the prima donna. this full contact fighting combines various martial arts techniques so fighters with different styles can compete against each other. this intriguing sport has convinced more than one athlete that he is not, in fact, the alpha and the omega! many people think that all combative sports should be strictly monitored and regulated by state commissions. it is obvious that the ultimate fighting championship (ufc) is an organization that promotes combative athletic events. state athletic commissions should strictly monitor and regulate the ufc.select the rebuttal statement that best refutes the viewpoint in section one. a) it is necessary to oversee the athletes involved in mixed martial arts. b) it is unnecessary to oversee the athletes involved in mixed martial arts. c) it is necessary for athletes involved in mixed martial arts to self-regulate. d) one distinctive feature of mixed martial arts is the combination of various techniques.

Iopened the door quietly,then stood in the doorway rewrite using ..ing participle