Question

The inflorescence in Gramineae is a
(a)Raceme
(b)Spike
(c)Spikelet
(d)Thyrsus

Answer 1

It is one of the flower bunches and the unit of inflorescence, which comprises at least two or more flowers and it is subtended by at least one or more glumes that can be differently arranged around a typical axis.

Complete answer:
Gramineae flower - Reproductive structures are distinct therein the inflorescences are made from sub inflorescences referred to as spikelets. The grass spikelet is characterized by two basal sterile bracts or glumes. These subtend either one (simple spikelet) or several (compound) florets. When floret applied to grasses, it alludes to the flower and two fertile bracts that generally encase the flower, the lemma, and palea. The perianth is diminished to negligible structures, lodicules, arranged underneath the ovary, and as needed, the fruit is single-developed with the testa adnate to the pericarp, a caryopsis. In contrast to most large families, the fruit is typically not needed for species identification. Along these lines, the inflorescence of Gramineae is spikelet and not raceme, spike, and thyrsus.

Additional information
Each spikelet has one or more florets. The spikelets are additionally gathered into panicles or spikes. The part of the spikelet that bears the florets is named the rachilla. A spikelet comprises two (or some of the timeless) bracts at the base, called glumes, trailed by at least one or more florets. A floret comprises the blossom encompassed by two bracts, one outer—the lemma—and one interior—the palea. The perianth is diminished to 2 scales, called lodicules, that stretch out and consent to spread the lemma and palea; these are generally unraveled to be changed sepals.
The flowers except that of Maize are usually hermaphroditic and pollination is mainly anemophilous or wind-pollinated, although insects occasionally play a task.

So the correct answer is ‘Spikelet’.

Note: Lemma is a cytomorphological term referring to a part of the spikelet. It is the lowermost of two debris like bracts encasing the grass floor. It often bears an extended bristle called an awn and should be similar in form to the glumes—chaffy bracts at the bottom of every spikelet. It is usually interpreted as a bract but it's also been interpreted together as a remnant (the abaxial) of the three members of outer perianth whorl (the palea may represent the opposite two members, having been joined together).